ap_pwrseq: Increase AP_PWRSEQ_STACK_SIZE

This is required to avoid stack overflow when triggering
system shutdown.

BUG=b:225756599
TEST=Boot SOC to OS; issue command 'shutdown -h now';
     System should power down to G3.
BRANCH=none

Signed-off-by: Perez Priego, Bernardo <bernardo.perez.priego@intel.com>
Change-Id: If7b67443b8d67ab1ff91e8b095cbcd4b28d3cabd
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3541339
Reviewed-by: Andrew McRae <amcrae@google.com>
Reviewed-by: Li1 Feng <li1.feng@intel.com>
Commit-Queue: Andrew McRae <amcrae@google.com>

Author: perezpri

zephyr/subsys/ap_pwrseq/Kconfig

@@ -32,7 +32,7 @@ config AP_PWRSEQ_AUTOSTART
 
 config AP_PWRSEQ_STACK_SIZE
 	int "AP pwrseq stack size (in bytes)"
-	default 800
+	default 1024
 	help
 	  This option specifies the size of the stack used by the
 	  AP power sequencing state machine thread handler.