asoc: codecs: bolero: Do not process ssr disable if already down

If codec receives ssr disable notification when
already in disabled state do not have to process it.
This makes sure codec register access are not done when
not necessary.

Change-Id: Iafc2b03d7c707c46c69ca995d36119929c34c222
Signed-off-by: Karthikeyan Mani <kmani@codeaurora.org>