greybus: operation: allow maximum-sized messages

Increase the maximum allowed buffer size to the full 16-bit range
supported by the protocol.

Note that host devices will generally use smaller buffers than the
maximum.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/operation.h

@@ -69,7 +69,7 @@ struct gb_operation_msg_hdr {
 	__u8	pad[2];		/* must be zero (ignore when read) */
 } __aligned(sizeof(u64));
 
-#define GB_OPERATION_MESSAGE_SIZE_MAX	4096
+#define GB_OPERATION_MESSAGE_SIZE_MAX	U16_MAX
 
 /*
  * Protocol code should only examine the payload and payload_size