media: intel/ipu6: make use of dev_err_cast_probe()

Using dev_err_cast_probe() to simplify the code.

No functional change.

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>