ASoC: stm32: properly get clk from the provider

Instead of using the clk embedded in the clk_hw (which is meant to go
away), a clock provider which need to interact with its own clock should
request clk reference through the clock provider API.

Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20210421120512.413057-2-jbrunet@baylibre.com


Signed-off-by: Mark Brown <broonie@kernel.org>