ASoC: wcd9335: Configure DMIC clock rate for ECPP path

DMIC clock on ECPP(Echo Cancellation Ping-Pong) hardware path
can run at lower clock rate to avoid power consumption. Select
ECPP dmic clock rate when decimator is connected only to ECPP
path.

CRs-fixed: 1022917
Change-Id: I968e1fe6b099ebf5334eadb209219181293b207f
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>
Signed-off-by: Vidyakumar Athota <vathota@codeaurora.org>