[AArch64] Update __gcsss intrinsic to match revised ACLE specification

The original __gcsss intrinsic was implemented based on:
ARM-software/acle#260
with the signature: const void *__gcsss(const void *)

Per the updated specification in:
ARM-software/acle#364
both const qualifiers have been removed. This commit updates the signature accordingly to:
void *__gcsss(void *)

This aligns the implementation with the latest ACLE definition.

Author: sivan-shani

clang/lib/Headers/arm_acle.h

@@ -841,8 +841,9 @@ __gcspopm() {
   return __builtin_arm_gcspopm(0);
 }
 
-static __inline__ const void * __attribute__((__always_inline__, __nodebug__, target("gcs")))
-__gcsss(const void *__stack) {
+static __inline__ void *
+    __attribute__((__always_inline__, __nodebug__, target("gcs")))
+    __gcsss(void *__stack) {
   return __builtin_arm_gcsss(__stack);
 }
 #endif