msm: sps: avoid accessing resources released by pipe disconnect

Client driver may have pipe connect and disconnect at the same
time. Adjust the locking location to avoid resource access in pipe
connect when pipe disconnect happens in parallel.

Change-Id: I76b5ab67516195709f634b6a536a0d02354960e1
Signed-off-by: Yan He <yanhe@codeaurora.org>