qcom: ssr: Unlock the ssr_order mutex before returning

Currently, the ssr_order_mutex is not unlocked if the function
returns early or with an error. Correct this to avoid deadlock.

Change-Id: I5c41723492fd912cf5279bc97bd5314856903050
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>