vidc: Fix for release of secure session.

When the video driver is released ,the memory is un protected
by calling the unsecure heap API, It was observed that
sometimes when the memory is unprotected without closing
the device the video core was not responding, after testing
it was found the call sequence of unprotecting and closing
of the video driver was not proper, hence first close the
video driver and then un protect the memory.

Change-Id: I35bd2b18281d78eb8ff91925f5b989282c2b5603
Signed-off-by: Deepak Kotur <dkotur@codeaurora.org>