staging: greybus: log: Fix line over 80 characters.

Fix coding style issue caught by checkpatch.pl related to the following
warning:
	- CHECK: WARNING: line over 80 characters
This is done by dropping a redundant cast and by replacing the format specifier
in dev_err(); to "%zu" instead of "%d", in order to silence the warnings of the
compiler.

Also, while at it, drop the redundant cast in the comparison as well to maintain
consistency.
Signed-off-by: Emmanuil Chatzipetru <chatzi.emanuel@gmail.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/log.c

@@ -37,9 +37,9 @@ static int gb_log_request_handler(struct gb_operation *op)
 	}
 	receive = op->request->payload;
 	len = le16_to_cpu(receive->len);
-	if (len != (int)(op->request->payload_size - sizeof(*receive))) {
-		dev_err(dev, "log request wrong size %d vs %d\n", len,
-				(int)(op->request->payload_size - sizeof(*receive)));
+	if (len != (op->request->payload_size - sizeof(*receive))) {
+		dev_err(dev, "log request wrong size %d vs %zu\n", len,
+				(op->request->payload_size - sizeof(*receive)));
 		return -EINVAL;
 	}
 	if (len == 0) {