AP_Periph: fixed moving baseline yaw for single CAN peripherals

the AP_GPS_UAVCAN driver requires this param for auto-config of MB yaw
on DroneCAN GPS

Tools/AP_Periph/Parameters.cpp

@@ -173,7 +173,7 @@ const AP_Param::Info AP_Periph_FW::var_info[] = {
     // @RebootRequired: True
     GSCALAR(gps_port, "GPS_PORT", HAL_PERIPH_GPS_PORT_DEFAULT),
 
-#if HAL_NUM_CAN_IFACES >= 2
+#if GPS_MOVING_BASELINE
     // @Param: MB_CAN_PORT
     // @DisplayName: Moving Baseline CAN Port option
     // @Description: Autoselect dedicated CAN port on which moving baseline data will be transmitted.

Tools/AP_Periph/Parameters.h

@@ -95,7 +95,7 @@ public:
 
 #ifdef HAL_PERIPH_ENABLE_GPS
     AP_Int8 gps_port;
-#if HAL_NUM_CAN_IFACES >= 2
+#if GPS_MOVING_BASELINE
     AP_Int8 gps_mb_only_can_port;
 #endif
 #endif