soc: swr-mstr-ctrl: Remove ssr_lock handling

During SSR and headset detection/removal interrupt
concurrencies, ssr_lock can lead to serv reg ack timeout
issues. Remove this synchronization to avoid this issue.

Change-Id: I242a013a7e9d833db21d737cbdfea2d84bbd29fa
Signed-off-by: Aditya Bavanari <abavanar@codeaurora.org>