AP_Notify: Add gps_num_sats

libraries/AP_GPS/AP_GPS.cpp

@@ -428,6 +428,7 @@ AP_GPS::update(void)
 
 	// update notify with gps status. We always base this on the primary_instance
     AP_Notify::flags.gps_status = state[primary_instance].status;
+    AP_Notify::flags.gps_num_sats = state[primary_instance].num_sats;
 }
 
 /*

libraries/AP_Notify/AP_Notify.h

@@ -55,6 +55,7 @@ public:
     struct notify_flags_type {
         uint32_t initialising       : 1;    // 1 if initialising and copter should not be moved
         uint32_t gps_status         : 3;    // 0 = no gps, 1 = no lock, 2 = 2d lock, 3 = 3d lock, 4 = dgps lock, 5 = rtk lock
+        uint32_t gps_num_sats       : 6;    // number of sats
         uint32_t armed              : 1;    // 0 = disarmed, 1 = armed
         uint32_t pre_arm_check      : 1;    // 0 = failing checks, 1 = passed
         uint32_t pre_arm_gps_check  : 1;    // 0 = failing pre-arm GPS checks, 1 = passed