hw/misc/stm32_rcc: Implement RCC device for STM32F4 SoCs

Generic RCC class for STM32 devices.  It can be used for most of
the STM32 chips.  Note that it only implements enable and reset
capabilities.

Signed-off-by: Roman Cardenas Rodriguez <rcardenas.rod@gmail.com>
[PMM: tweaked commit message, added MAINTAINERS lines]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
6 files changed