Add default value protection for line coding parameters in serial Host classes

Add preprocessor guards to allow customization of default line coding parameters.

Summary of Changes:
- Wrapped default line coding constants (RATE, STOP_BIT, PARITY, DATA_BIT)
  with #ifndef guards in CDC ACM, GSER, and Prolific host class headers
- This allows users to define custom default values before including these headers in (ux_user.h)
- Updated Prolific activation code to use DEFAULT constants instead of hardcoded values
  for consistency and better maintainability

Files Modified:
- common/usbx_host_classes/inc/ux_host_class_cdc_acm.h
- common/usbx_host_classes/inc/ux_host_class_gser.h
- common/usbx_host_classes/inc/ux_host_class_prolific.h
- common/usbx_host_classes/src/ux_host_class_prolific_activate.c

Author: ayedm1

common/usbx_host_classes/inc/ux_host_class_cdc_acm.h

@@ -135,10 +135,21 @@ extern   "C" {
 
 /* Define CDC ACM default values.  */
 
+#ifndef UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_RATE
 #define UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_RATE          9600
+#endif
+
+#ifndef UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_STOP_BIT
 #define UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_STOP_BIT      0
+#endif
+
+#ifndef UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_PARITY
 #define UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_PARITY        0
+#endif
+
+#ifndef UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_DATA_BIT
 #define UX_HOST_CLASS_CDC_ACM_LINE_CODING_DEFAULT_DATA_BIT      8
+#endif
 
 /* Define CDC ACM line coding definitions.  */
 

common/usbx_host_classes/inc/ux_host_class_gser.h

@@ -115,8 +115,21 @@ extern   "C" {
 
 /* Define CDC ACM default values.  */
 
+#ifndef UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_RATE
 #define UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_RATE             9600
+#endif
+
+#ifndef UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_STOP_BIT
+#define UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_STOP_BIT         0
+#endif
+
+#ifndef UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_PARITY
+#define UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_PARITY           0
+#endif
+
+#ifndef UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_DATA_BIT
 #define UX_HOST_CLASS_GSER_LINE_CODING_DEFAULT_DATA_BIT         8
+#endif
 
 /* Define CDC ACM line coding definitions.  */
 

common/usbx_host_classes/inc/ux_host_class_prolific.h

@@ -144,8 +144,21 @@ extern   "C" {
 
 /* Define  PROLIFIC default values.  */
 
+#ifndef UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_RATE
 #define UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_RATE         19200
+#endif
+
+#ifndef UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_STOP_BIT
+#define UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_STOP_BIT     0
+#endif
+
+#ifndef UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_PARITY
+#define UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_PARITY       0
+#endif
+
+#ifndef UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_DATA_BIT
 #define UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_DATA_BIT     8
+#endif
 
 /* Define  PROLIFIC line coding definitions.  */
 

common/usbx_host_classes/src/ux_host_class_prolific_activate.c

@@ -125,8 +125,8 @@ UINT                                status;
     if (status == UX_SUCCESS)
     {
         line_coding.ux_host_class_prolific_line_coding_dter      = UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_RATE;
-        line_coding.ux_host_class_prolific_line_coding_stop_bit  = UX_HOST_CLASS_PROLIFIC_LINE_CODING_STOP_BIT_0;
-        line_coding.ux_host_class_prolific_line_coding_parity    = UX_HOST_CLASS_PROLIFIC_LINE_CODING_PARITY_NONE;
+        line_coding.ux_host_class_prolific_line_coding_stop_bit  = UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_STOP_BIT;
+        line_coding.ux_host_class_prolific_line_coding_parity    = UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_PARITY;
         line_coding.ux_host_class_prolific_line_coding_data_bits = UX_HOST_CLASS_PROLIFIC_LINE_CODING_DEFAULT_DATA_BIT;
         status = _ux_host_class_prolific_ioctl(prolific, UX_HOST_CLASS_PROLIFIC_IOCTL_SET_LINE_CODING, (VOID *) &line_coding);
     }