ASoC: msm8x16-wcd: Avoid codec read/writes if device is down

When SSR happens, read and write codec registers over
AHB and SPMI cannot be performed. Set codec device down whenever
device down notification from SSR framework is received so that
register read and writes can be avoided safely. Later when
device up notification is received, codec device down state
will be cleared and register read/writes can be allowed.
Update the sequence in codec device down and device up.

Change-Id: Ie55c0ff78499f018f13d2489c335be50f9455ecd
Signed-off-by: Aravind Kumar <akumark@codeaurora.org>