Update HALConfig.h

Added declaration for new hal routine to enable Dual Mode in HW

Author: jmdodd95682

src/HALConfig.h

@@ -30,5 +30,6 @@ void hal_dma_enable_dbm(DMA_HandleTypeDef *dma, void *m0 = nullptr, void *m1 = n
 void hal_dma_update_memory(DMA_HandleTypeDef *dma, void *addr);
 int hal_dac_config(DAC_HandleTypeDef *dac, uint32_t channel, uint32_t trigger);
 int hal_adc_config(ADC_HandleTypeDef *adc, uint32_t resolution, uint32_t trigger, PinName *adc_pins, uint32_t n_channels);
+int hal_enable_dual_mode();
 
 #endif  // __HAL_CONFIG_H__