stm32f7

Cleanup stm32f7 files:
- use BIT macro
- use GENMASK macro
- use rcc struct instead of macro additions

Add missing stm32f7 register in rcc struct

Signed-off-by: Michael Kurz <michi.kurz@gmail.com>
Acked-by: Vikas <MANOCHA&lt;vikas.manocha@st.com>