msm: vidc: Fix a bug in state transition

Fix a bug in state transition in driver. Without this
fix some of the buffers were not released on firmware
in following scenario:

1. Video device is openend.
2. Buffers are allocated.
3. Video device is closed.

This change fixes this issue.
CRs-fixed: 419927

Change-Id: I5f27b047971bcf1fb85e45a8c9d9938e177a4de5
Signed-off-by: Vinay Kalia <vkalia@codeaurora.org>