staging: greybus: shorten comparison to NULL

Shorten pointer NULL check by simple truth test.
Reported by checkpatch.
Signed-off-by: Ioannis Valasakis <code@wizofe.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/core.c

@@ -48,7 +48,7 @@ static bool greybus_match_one_id(struct gb_bundle *bundle,
 static const struct greybus_bundle_id *
 greybus_match_id(struct gb_bundle *bundle, const struct greybus_bundle_id *id)
 {
-	if (id == NULL)
+	if (!id)
 		return NULL;
 
 	for (; id->vendor || id->product || id->class || id->driver_info;