ACMotors: remove unused get_num_motors function

Saves about 4 bytes of RAM

libraries/AP_Motors/AP_MotorsHeli.h

@@ -108,11 +108,6 @@ public:
     // enable - starts allowing signals to be sent to motors
     void enable();
 
-    // get basic information about the platform
-    uint8_t get_num_motors() {
-        return 5;
-    };
-
     // motor test
     void output_test();
 

libraries/AP_Motors/AP_MotorsMatrix.h

@@ -42,11 +42,6 @@ public:
     // enable - starts allowing signals to be sent to motors
     virtual void        enable();
 
-    // get basic information about the platform
-    virtual uint8_t         get_num_motors() {
-        return _num_motors;
-    };
-
     // motor test
     virtual void        output_test();
 

libraries/AP_Motors/AP_MotorsTri.h

@@ -33,11 +33,6 @@ public:
     // enable - starts allowing signals to be sent to motors
     virtual void        enable();
 
-    // get basic information about the platform
-    virtual uint8_t         get_num_motors() {
-        return 4;
-    };                                                  // 3 motors + 1 tail servo
-
     // motor test
     virtual void        output_test();
 

libraries/AP_Motors/AP_Motors_Class.h

@@ -117,11 +117,6 @@ public:
         return _reached_limit & which_limit;
     }
 
-    // get basic information about the platform
-    virtual uint8_t        get_num_motors() {
-        return 0;
-    };
-
     // motor test
     virtual void        output_test() {
     };