ASoC: wsa-macro: Fix APSS crash if wsa swr master is disabled

If wsa swr master is disabled, swr_ctrl_data for wsa_priv
will be NULL. Add NULL check for swr_ctrl_data and
return to fix the crash.

Change-Id: I6cdaa0a46be2845ed7016b032cfe3260062f6c7f
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>