Spectrum bind code to be more geenic

Actualy only activated for the NAZE taget for USART2

#define SPEKTRUM_BIND
#define BIND_PORT  GPIOA
#define BIND_PIN   Pin_3

This is to activate the Hardware bind pug feature
#define HARDWARE_BIND_PLUG
#define BINDPLUG_PORT  GPIOB
#define BINDPLUG_PIN   Pin_5

can now be easyly added and configured for other tagets after testing.

src/main/main.c

@@ -150,6 +150,7 @@ void init(void)
 
     systemInit();
 
+#ifdef SPEKTRUM_BIND
     // Spektrum sattelite bind - ported from Baseflight
     if (feature(FEATURE_RX_SERIAL)) {
         switch (masterConfig.rxConfig.serialrx_provider) {
@@ -162,6 +163,7 @@ void init(void)
                 break;
         }
     }
+#endif
 
     delay(100);