drm/msm/sde: decrement pending_retire_fence_cnt on timeout

Decrement the pending retire fence count when
encountering a timeout while waiting for the
vblank interrupt. This change will prevent the
retire and release fences from being signalled
extra times and hence will prevent the printing
of associated error messages. Also added another
wrapper for the encoder's wait_for_vblank because
it does not require a frame done notification.

Change-Id: Ia0771f09f12e794f1996e6fef5510eb115f96e31
Signed-off-by: Fuad Hossain <fhossain@codeaurora.org>