selftests/seccomp: remove ARRAY_SIZE define from seccomp_benchmark

ARRAY_SIZE is defined in several selftests. Remove definitions from
individual test files and include header file for the define instead.
ARRAY_SIZE define is added in a separate patch to prepare for this
change.

Remove ARRAY_SIZE from seccomp_benchmark and pickup the one defined in
kselftest.h.
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/seccomp/seccomp_benchmark.c

@@ -18,7 +18,7 @@
 #include <sys/syscall.h>
 #include <sys/types.h>
 
-#define ARRAY_SIZE(a)    (sizeof(a) / sizeof(a[0]))
+#include "../kselftest.h"
 
 unsigned long long timing(clockid_t clk_id, unsigned long long samples)
 {