ASoC: wcd9335: Update wcd9335 codec volatile register

Declare mclk and SIDO buck related registers as volatile
so that read/writes to these registers will always happen
from/to codec hardware. It is possible that these registers
will be updated by hardware before even regmap cache is
initialized, so declaring them as volatile will always
get the correct values as per hardware state.

Change-Id: I59412a5c6f64eab8d983cd4f4eb4e0524b91866e
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>