AP_HAL_VRBrain: attach_interrupt now takes a functor

AP_HAL_VRBRAIN: add type-safety for interrupt types

libraries/AP_HAL_VRBRAIN/GPIO.cpp

@@ -173,7 +173,9 @@ AP_HAL::DigitalSource* VRBRAINGPIO::channel(uint16_t n) {
 }
 
 /* Interrupt interface: */
-bool VRBRAINGPIO::attach_interrupt(uint8_t interrupt_num, AP_HAL::Proc p, uint8_t mode)
+bool VRBRAINGPIO::attach_interrupt(uint8_t interrupt_num,
+                                   irq_handler_fn_t fn,
+                                   INTERRUPT_TRIGGER_TYPE mode)
 {
     return true;
 }

libraries/AP_HAL_VRBRAIN/GPIO.h

@@ -31,7 +31,9 @@ public:
     AP_HAL::DigitalSource* channel(uint16_t n) override;
 
     /* Interrupt interface: */
-    bool attach_interrupt(uint8_t interrupt_num, AP_HAL::Proc p, uint8_t mode) override;
+    bool attach_interrupt(uint8_t interrupt_num,
+                          irq_handler_fn_t fn,
+                          INTERRUPT_TRIGGER_TYPE mode) override;
 
     /* return true if USB cable is connected */
     bool usb_connected(void) override;