msm: camera: csiphy: Clear secure phy flags on release

Issue:
Phy flags are set on CONFIG_DEV and are cleared on STOP_DEV.
If release is called without stop dev, next session will be opened with
incorrect phy configuration based on the previous stale secure mode
flags.

Fix:
Clear the phy secure mode flags on RELEASE_DEV.

Change-Id: If47a4084c3edbf2a8fb48d22b85c5d04fe878c50
Signed-off-by: Shankar Ravi <rshankar@codeaurora.org>