msm: camera: core: Check context state prior to handle release

This change adds a state check for context before calling a
release on dev handle in order to prevent a release call on
a previously deinitialized context.

Change-Id: I35eedc0b3662c9b556f1e54d19cccc09d15023ab
Signed-off-by: Venkat Chinta <vchinta@codeaurora.org>