selftests, arm64: fix uninitialized symbol in tags_test.c

Fix tagged_ptr not being initialized when TBI is not enabled.

Link: https://www.spinics.net/lists/linux-kselftest/msg09446.html
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Will Deacon <will@kernel.org>

tools/testing/selftests/arm64/tags_test.c

@@ -14,15 +14,17 @@
 int main(void)
 {
 	static int tbi_enabled = 0;
-	struct utsname *ptr, *tagged_ptr;
+	unsigned long tag = 0;
+	struct utsname *ptr;
 	int err;
 
 	if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)
 		tbi_enabled = 1;
 	ptr = (struct utsname *)malloc(sizeof(*ptr));
 	if (tbi_enabled)
-		tagged_ptr = (struct utsname *)SET_TAG(ptr, 0x42);
-	err = uname(tagged_ptr);
+		tag = 0x42;
+	ptr = (struct utsname *)SET_TAG(ptr, tag);
+	err = uname(ptr);
 	free(ptr);
 
 	return err;