drivers: reset: Introduce STM32 reset controller

This driver exposes STM32 RCC reset functionality through reset API.

Information about RCC register offset and bit is encoded just like GD32.
The first 5 least significant bits contains register bit number.
Next 12 bits are used to keep RCC register offset. Remaining bits are
unused.

Signed-off-by: Patryk Duda <pdk@semihalf.com>