media: exynos: mfc: do not release firmware buffer when drm is enabled

The release function already had this check but the error paths in
open did not.

Change-Id: Ida0173787b86ce9df7656dc8e62c07f13916747d
Signed-off-by: Dima Zavin <dima@android.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>