media: exynos4-is: Fix several reference count leaks due to pm_runtime_get_sync

On calling pm_runtime_get_sync() the reference count of the device
is incremented. In case of failure, decrement the
reference count before returning the error.

Signed-off-by: Qiushi Wu <wu000273@umn.edu>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>