[project][generic-arm] Enable kernel shadow call stack

Enable kernel shadow call stack for 64-bit generic-arm kernels.

Test: build.py qemu-generic-arm64-test-debug
Bug: 79994372
Change-Id: Ic32cf8d6195c907e56aaf652ee0a17f696070f0a
diff --git a/project/generic-arm-inc.mk b/project/generic-arm-inc.mk
index 2de647d..253bc12 100644
--- a/project/generic-arm-inc.mk
+++ b/project/generic-arm-inc.mk
@@ -101,6 +101,7 @@
 endif
 
 ifeq (false,$(call TOBOOL,$(KERNEL_32BIT)))
+KERNEL_SCS_ENABLED ?= true
 ifeq (false,$(call TOBOOL,$(USER_32BIT)))
 # enable shadow call stack in user-tasks modules
 USER_SCS_ENABLED ?= true