Update HALConfig.h

Forgot disable method for Dual Mode

Author: jmdodd95682

src/HALConfig.h

@@ -31,5 +31,6 @@ 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();
+int hal_disable_dual_mode();
 
 #endif  // __HAL_CONFIG_H__