greybus: fix op_cycle logic

The function that computes the operation id for a connection is
wrongly using MOD rather than AND.  Fix that.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/connection.c

@@ -171,7 +171,7 @@ void gb_connection_destroy(struct gb_connection *connection)
 
 u16 gb_connection_operation_id(struct gb_connection *connection)
 {
-	return (u16)(atomic_inc_return(&connection->op_cycle) % U16_MAX);
+	return (u16)(atomic_inc_return(&connection->op_cycle) & (int)U16_MAX);
 }
 
 void gb_connection_err(struct gb_connection *connection, const char *fmt, ...)