Fix typos with #ifdef's.

Signed-off-by: CAI Qian <caiqian@redhat.com>
diff --git a/testcases/kernel/mem/oom/oom02.c b/testcases/kernel/mem/oom/oom02.c
index 04c6507..adb4d52 100644
--- a/testcases/kernel/mem/oom/oom02.c
+++ b/testcases/kernel/mem/oom/oom02.c
@@ -53,7 +53,7 @@
 	if ((msg = parse_opts(argc, argv, NULL, NULL)) != NULL)
 		tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);
 
-#ifdef __WORDSIZE == 32
+#if __WORDSIZE == 32
 	tst_brkm(TCONF, NULL, "test is not designed for 32-bit system.");
 #endif