selftests/x86/syscall: Fix coccinelle WARNING recommending the use of ARRAY_SIZE()

Coccinelle gives WARNING recommending the use of ARRAY_SIZE() macro definition
to improve the code readability:

  ./tools/testing/selftests/x86/syscall_numbering.c:316:35-36: WARNING: Use ARRAY_SIZE

Fixes: 15c82d98a0 ("selftests/x86/syscall: Update and extend syscall_numbering_64")
Signed-off-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20241101111523.1293193-2-mtodorovac69@gmail.com

tools/testing/selftests/x86/syscall_numbering.c

@@ -25,6 +25,7 @@
 #include <sys/mman.h>
 
 #include <linux/ptrace.h>
+#include "../kselftest.h"
 
 /* Common system call numbers */
 #define SYS_READ	  0
@@ -313,7 +314,7 @@ static void test_syscall_numbering(void)
 	 * The MSB is supposed to be ignored, so we loop over a few
 	 * to test that out.
 	 */
-	for (size_t i = 0; i < sizeof(msbs)/sizeof(msbs[0]); i++) {
+	for (size_t i = 0; i < ARRAY_SIZE(msbs); i++) {
 		int msb = msbs[i];
 		run("Checking system calls with msb = %d (0x%x)\n",
 		    msb, msb);