drivers: adc: stm32h7 adc driver has a different oversampling ratio
drivers: adc: stm32h7 adc driver has a different oversampling ratio

The adc_stm32_oversampling function is used to configure
the ratio and shift for each sequence->oversampling
depending on the soc serie and ADC instance in the serie
In the stm32H7 serie, only ADC3 of ADC_VER_V5_V90 version
have a LL_ADC_OVS_RATIO_x contant (other a 9bit value).

Signed-off-by: Francois Ramu <b83adc7f8a23ee911a37fcb61c4033581aae0b7a@st.com>

finikorg/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr