selftests/powerpc: Create a new SKIP_IF macro

This patch creates a new macro that skips a test and prints a message to
stderr. This is useful to give an idea why the tests is being skipped,
other than just skipping the test blindly.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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

@@ -82,6 +82,16 @@ do {								\
 	}							\
 } while (0)
 
+#define SKIP_IF_MSG(x, msg)					\
+do {								\
+	if ((x)) {						\
+		fprintf(stderr,					\
+		"[SKIP] Test skipped on line %d: %s\n",		\
+		 __LINE__, msg);				\
+		return MAGIC_SKIP_RETURN_VALUE;			\
+	}							\
+} while (0)
+
 #define _str(s) #s
 #define str(s) _str(s)