staging: android: sync: fix list corruption in fence struct

Fence lock is not taken in sync_print_fence() while calling
sync_print_pt() which in turn calls fence_is_signaled() to check the
status of each fence before printing. This creates a race condition
that corrupts fence data structure when another thread calls
fence_is_signaled_locked() on the same fence. Since we don't need to
signal the fence while logging, it can be fixed by simply checking fence
flag status directly instead of calling fence_is_signaled_locked().

Change-Id: I1b4732cf3779a5b75a372e11170b438a4deabe67
Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org>