adc_set_resolution bug

in `adc.c`:
```c
void adc_set_resolution(Adc *p_adc,const enum adc_resolution_t resolution)
{
p_adc->ADC_MR |= (resolution << 4) & ADC_MR_LOWRES;
}
```

is incorrect. The RHS always evaluates to 0 since the valid values of `enum adc_resolution_t` as seen in `adc.h` are 0 (`ADC_12_BITS`), or 16 (`ADC_10_BITS`)

Read adc.c at adc_set_resolution and check the enum values in adc.h first. Verify the resolution bits are updated according to the valid ADC_12_BITS and ADC_10_BITS values, then confirm the function no longer leaves the relevant setting unchanged.

Written by the indexing model from the issue text.