media: exynos: s5p-mfc: prevent suspend while MFC is in use

Change-Id: I6beecbdcb828c20af0f32c1af4d97a163867786a
Signed-off-by: Dima Zavin <dima@android.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>