AP_BoardConfig: allow PWM count setting on all chibios boards

libraries/AP_BoardConfig/AP_BoardConfig.cpp

@@ -93,7 +93,7 @@ AP_BoardConfig *AP_BoardConfig::instance;
 
 // table of user settable parameters
 const AP_Param::GroupInfo AP_BoardConfig::var_info[] = {
-#if AP_FEATURE_BOARD_DETECT
+#if AP_FEATURE_BOARD_DETECT || defined(AP_FEATURE_BRD_PWM_COUNT_PARAM)
     // @Param: PWM_COUNT
     // @DisplayName: Auxiliary pin config
     // @Description: Control assigning of FMU pins to PWM output, timer capture and GPIO. All unassigned pins can be used for GPIO

libraries/AP_BoardConfig/AP_BoardConfig.h

@@ -118,7 +118,7 @@ public:
 
     // get number of PWM outputs enabled on FMU
     static uint8_t get_pwm_count(void) {
-#if AP_FEATURE_BOARD_DETECT
+#if AP_FEATURE_BOARD_DETECT || defined(AP_FEATURE_BRD_PWM_COUNT_PARAM)
         return instance?instance->state.pwm_count.get():4;
 #else
         return 0;
@@ -144,7 +144,7 @@ private:
     
     AP_Int16 vehicleSerialNumber;
 
-#if AP_FEATURE_BOARD_DETECT
+#if AP_FEATURE_BOARD_DETECT || defined(AP_FEATURE_BRD_PWM_COUNT_PARAM)
     struct {
         AP_Int8 pwm_count;
         AP_Int8 safety_enable;
@@ -158,7 +158,9 @@ private:
         AP_Int8 board_type;
         AP_Int8 io_enable;
     } state;
+#endif
 
+#if AP_FEATURE_BOARD_DETECT
     static enum px4_board_type px4_configured_board;
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_PX4 || CONFIG_HAL_BOARD == HAL_BOARD_VRBRAIN