ArduCopter: remove redundant check for home-is-set

this is done as part of the frame change

Author: peterbarker

ArduCopter/inertia.cpp

@@ -20,7 +20,7 @@ void Copter::read_inertia()
     // current_loc.alt is alt-above-home, converted from inertial nav's alt-above-ekf-origin
     const int32_t alt_above_origin_cm = inertial_nav.get_position_z_up_cm();
     current_loc.set_alt_cm(alt_above_origin_cm, Location::AltFrame::ABOVE_ORIGIN);
-    if (!ahrs.home_is_set() || !current_loc.change_alt_frame(Location::AltFrame::ABOVE_HOME)) {
+    if (current_loc.initialised() && !current_loc.change_alt_frame(Location::AltFrame::ABOVE_HOME)) {
         // if home has not been set yet we treat alt-above-origin as alt-above-home
         current_loc.set_alt_cm(alt_above_origin_cm, Location::AltFrame::ABOVE_HOME);
     }