dt-bindings: Document the STM32F4 clock bindings

This adds documentation of device tree bindings for the clock related
portions of the STM32 RCC block.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
1 file changed