selftests/powerpc: Add helper to exit on failure

This adds a helper similar to FAIL_IF() which lets a
program exit with code 1 (to indicate failure) when
the given condition is true.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/dac282d5c2e96e7816dc522e4e20d56d7c79c898.1595821792.git.sandipan@linux.ibm.com

tools/testing/selftests/powerpc/include/utils.h

@@ -72,6 +72,15 @@ do {								\
 	}							\
 } while (0)
 
+#define FAIL_IF_EXIT(x)						\
+do {								\
+	if ((x)) {						\
+		fprintf(stderr,					\
+		"[FAIL] Test FAILED on line %d\n", __LINE__);	\
+		_exit(1);					\
+	}							\
+} while (0)
+
 /* The test harness uses this, yes it's gross */
 #define MAGIC_SKIP_RETURN_VALUE	99