Introduce tst_parse_opts()

The pattern that was used in all testcases is:

const char *msg;

msg = parse_opts(...);
if (msg)
	tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);

This change simplifies the steps to just calling:

tst_parse_opts(...);

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
diff --git a/testcases/kernel/mem/oom/oom02.c b/testcases/kernel/mem/oom/oom02.c
index 0d4c7c7..fce0110 100644
--- a/testcases/kernel/mem/oom/oom02.c
+++ b/testcases/kernel/mem/oom/oom02.c
@@ -47,12 +47,9 @@
 
 int main(int argc, char *argv[])
 {
-	const char *msg;
 	int lc;
 
-	msg = parse_opts(argc, argv, NULL, NULL);
-	if (msg != NULL)
-		tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);
+	tst_parse_opts(argc, argv, NULL, NULL);
 
 #if __WORDSIZE == 32
 	tst_brkm(TCONF, NULL, "test is not designed for 32-bit system.");