greybus: svc: error out only for smaller payloads received

!= was used in place of <, while comparing expected and actual payload
size. The module may be running a higher version of the protocol and
might have some extra fields (towards the end) in the structure, and the
AP needs to ignore them.

This also updates the print (expected-payload-size <
actual-payload-size), when the size doesn't match for requests received
by the module. This gives more details required for debugging.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/svc.c

@@ -193,8 +193,8 @@ static int gb_svc_hello(struct gb_operation *op)
 	 * SVC sends information about the endo and interface-id on the hello
 	 * request, use that to create an endo.
 	 */
-	if (op->request->payload_size != sizeof(*hello_request)) {
-		dev_err(dev, "%s: Illegal size of hello request (%zu %zu)\n",
+	if (op->request->payload_size < sizeof(*hello_request)) {
+		dev_err(dev, "%s: Illegal size of hello request (%zu < %zu)\n",
 			__func__, op->request->payload_size,
 			sizeof(*hello_request));
 		return -EINVAL;