q6afe already exposes lpass clocks, however this was not presented
as proper clock controller driver. This patch basically adds clock
controller support for q6afe clocks.

This is useful for other drivers like lpass digital codec or lpass
lowpower island drivers to request or vote for these clocks.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200910135708.14842-3-srinivas.kandagatla@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>