media: rockchip: rga: Fix probe rga_parse_dt bugs

rga_parse_dt is missing a error return, so if some of the resources
return DEFER_PROBE, probe will succeed without these resources.

Signed-off-by: Ondrej Jirman <megi@xff.cz>
Co-developed-by: Jarrah Gosbell <kernel@undef.tools>
Signed-off-by: Jarrah Gosbell <kernel@undef.tools>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>