msm: kgsl: Correct locking in timeline destroy and fence release

Both "timeline->lock" and "fence_lock" are required to be held
while accessing timeline fence list and "timeline->lock" is
required to be held while signaling timeline fences. This is
not followed during timeline destroy and fence release resulting
in an invalid fence pointer access during timeline destroy. Fix
this by acquiring required locks at both places.

Change-Id: I353a6b9dece666c25d702c004a8bdabcac6d10a3
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>