drivers: adc: make use of new stm32 adc compatibles

Several sections of the STM32 ADC driver are #ifdef by a combination of the
same SOC defines that share similar IPs. These are F2/F4/F7/L1, and
F1/F37x.
Each of these combinations is now replaced by a specific compatible, which
makes the code a bit lighter and more succinct.

Signed-off-by: Guillaume Gautier <guillaume.gautier-ext@st.com>