HAL_ChibiOS: fixed BRD_SAFETY_MASK on some boards

for boards that have an IOMCU but also have a safety button on the FMU
this fixes the BRD_SAFETY_MASK

libraries/AP_HAL_ChibiOS/RCOutput.cpp

@@ -2092,6 +2092,11 @@ void RCOutput::safety_update(void)
     }
 #elif HAL_WITH_IO_MCU
     safety_state = _safety_switch_state();
+#endif
+
+#if HAL_WITH_IO_MCU
+    // regardless of if we have a FMU safety pin, if we have an IOMCU we need
+    // to pass the BRD_SAFETY_MASK to the IOMCU
     iomcu.set_safety_mask(safety_mask);
 #endif