ASoC: stm32: add clock dependency for sai

Fixes: 8307b2af

 ("ASoC: stm32: sai: set sai as mclk clock provider")

Add COMMON_CLK dependency for STM32 SAI,
as it is required by clock provider.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>