app: debug: enable xtensa adsp fatal exception breadcrumbs

Enable CONFIG_XTENSA_ADSP_FATAL_BREADCRUMB in the debug overlay so debug
builds record the faulting PC/cause/vaddr into HP-SRAM window0, making a
crash visible in the host dmesg "Firmware state" line when no console or
mtrace output is available. The option defaults to n, so production
builds (which do not pull in this overlay) are unaffected.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

Author: lrgirdwo

app/debug_overlay.conf

@@ -31,3 +31,8 @@ CONFIG_GDBSTUB_ENTER_IMMEDIATELY=n
 # Testing with runtime filtering enabled ensures the same feature set is validated.
 # Note: This setting has no effect if CONFIG_LOG_RUNTIME_FILTERING is disabled.
 CONFIG_LOG_RUNTIME_DEFAULT_LEVEL=3
+
+# Record fatal exception breadcrumbs (PC/cause/vaddr) in HP-SRAM window0 so the
+# crash is visible in the host dmesg "Firmware state" line when no console or
+# mtrace output is available.
+CONFIG_XTENSA_ADSP_FATAL_BREADCRUMB=y