GCS_MAVLink: add Board option to disable MAVftp in low mem bds/apps

libraries/GCS_MAVLink/GCS_Common.cpp

@@ -5065,8 +5065,10 @@ uint64_t GCS_MAVLINK::capabilities() const
         ret |= MAV_PROTOCOL_CAPABILITY_MISSION_FENCE;
     }
 
-    ret |= MAV_PROTOCOL_CAPABILITY_FTP;
-
+    if (!AP_BoardConfig::ftp_disabled()){  //if ftp disable board option is not set
+        ret |= MAV_PROTOCOL_CAPABILITY_FTP;
+    }
+ 
     return ret;
 }
 

libraries/GCS_MAVLink/GCS_FTP.cpp

@@ -20,6 +20,7 @@
 
 #include <AP_Filesystem/AP_Filesystem.h>
 #include <AP_HAL/utility/sparse-endian.h>
+#include <AP_BoardConfig/AP_BoardConfig.h>
 
 extern const AP_HAL::HAL& hal;
 
@@ -29,7 +30,14 @@ struct GCS_MAVLINK::ftp_state GCS_MAVLINK::ftp;
 #define FTP_SESSION_TIMEOUT 3000
 
 bool GCS_MAVLINK::ftp_init(void) {
+
+    // check if ftp is disabled for memory savings
+    if (AP_BoardConfig::ftp_disabled()) {
+        goto failed;
+    }
+
     // we can simply check if we allocated everything we need
+
     if (ftp.requests != nullptr) {
         return true;
     }