GCS_MAVLink: fixed const in buffer based send call

libraries/GCS_MAVLink/include/mavlink/v1.0/mavlink_helpers.h

@@ -117,6 +117,7 @@ MAVLINK_HELPER void _mav_finalize_message_chan_send(mavlink_channel_t chan, uint
 	buf[4] = mavlink_system.compid;
 	buf[5] = msgid;
 	status->current_tx_seq++;
+
 	checksum = crc_calculate((uint8_t*)&buf[1], MAVLINK_CORE_HEADER_LEN);
 	crc_accumulate_buffer(&checksum, packet, length);
 #if MAVLINK_CRC_EXTRA
@@ -511,7 +512,7 @@ MAVLINK_HELPER void _mavlink_send_uart(mavlink_channel_t chan, const char *buf,
 #ifdef MAVLINK_SEND_UART_BYTES
 	/* this is the more efficient approach, if the platform
 	   defines it */
-	MAVLINK_SEND_UART_BYTES(chan, (uint8_t *)buf, len);
+	MAVLINK_SEND_UART_BYTES(chan, (const uint8_t *)buf, len);
 #else
 	/* fallback to one byte at a time */
 	uint16_t i;