RC_Channel: add get_channel_pos function

libraries/RC_Channel/RC_Channel.cpp

@@ -997,6 +997,14 @@ RC_Channel::aux_switch_pos_t RC_Channel::get_aux_switch_pos() const
     return position;
 }
 
+// return switch position value as LOW, MIDDLE, HIGH
+// if reading the switch fails then it returns LOW
+RC_Channel::aux_switch_pos_t RC_Channels::get_channel_pos(const uint8_t rcmapchan) const
+{
+    const RC_Channel* chan = rc().channel(rcmapchan-1);
+    return chan != nullptr ? chan->get_aux_switch_pos() : RC_Channel::aux_switch_pos_t::LOW;
+}
+
 RC_Channel *RC_Channels::find_channel_for_option(const RC_Channel::aux_func_t option)
 {
     for (uint8_t i=0; i<NUM_RC_CHANNELS; i++) {

libraries/RC_Channel/RC_Channel.h

@@ -324,6 +324,7 @@ public:
 
     class RC_Channel *find_channel_for_option(const RC_Channel::aux_func_t option);
     bool duplicate_options_exist();
+    RC_Channel::aux_switch_pos_t get_channel_pos(const uint8_t rcmapchan) const;
 
     void init_aux_all();
     void read_aux_all();