MicroPython: fix support for machine module

Author: ccattuto

advanced/micropython/port-riscv-emu.py/modmachine_port.c

@@ -0,0 +1,7 @@
+// Imported via MICROPY_PY_MACHINE_INCLUDEFILE in mpconfigport.h
+
+// Provide mp_machine_idle implementation
+static void mp_machine_idle(void) {
+    // In a real embedded system, this would execute WFI (Wait For Interrupt)
+    // For the emulator, we just return immediately
+}