GCS_MAVLink: Bug - CLI_ENABLED check should be in vehicle code only.

Changes to fix the warnings in rover sitl build.
We are starting the process of resolving all the warnings in the
ardupilot builds of all vehicles and platforms.

libraries/GCS_MAVLink/GCS.h

@@ -185,10 +185,8 @@ private:
     mavlink_channel_t           chan;
     uint16_t                    packet_drops;
 
-#if CLI_ENABLED == ENABLED
     // this allows us to detect the user wanting the CLI to start
     uint8_t        crlf_count;
-#endif
 
     // waypoints
     uint16_t        waypoint_request_i; // request index