ASoC: sdm660_cdc: Avoid unclocked register access to digital codec

In particular SSR scenario, digital codec access happens without
clock enabled. While SSR down event notification in progress,
APR driver blocks request to DSP to enable clock since APR already
received down event. regmap access to digital codec register results in
AHB timeout error. If DSP clock enable request fails, set the regmap
access cache only mode to avoid any register access.

CRs-Fixed: 2034468
Change-Id: Id1141339d2673920167ed7ac74b13b6fee05173f
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>