clock_control: stm32f4x: introduce driver for STM32F4x RCC

Based on the STM32F10x driver. Removing old code as we need to use the
bus number when dealing with 4 possible peripherals.

Change-Id: Id0263aa008e9b039ff9a00339e5622e289ffdf99
Signed-off-by: Ricardo Salveti <ricardo.salveti@linaro.org>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
9 files changed