media: rockchip: rkisp1: destage Rockchip ISP1 driver

All the items in the TODO list were addressed, uapi was reviewed,
documentation written, checkpatch errors fixed, several bugs fixed.

There is no big reason to keep this driver in staging, so move it out.

Dt-bindings Verified with:
make ARCH=arm64 dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/media/rockchip-isp1.yaml

Fields of MAINTAINERS file sorted according to output of
./scripts/parse-maintainers.pl --input=MAINTAINERS --output=MAINTAINERS
--order

Signed-off-by: Helen Koike <helen.koike@collabora.com>
[dt-bindings: media: rkisp1: move rockchip-isp1 bindings out of staging]
Acked-by: Rob Herring <robh@kernel.org>
[dt-bindings: media: rkisp1: move rockchip-isp1 bindings out of staging]
Reviewed-by: Tomasz Figa <tfiga@chromium.org>

---
Changes in v3:
- Moved Kconfig entry from M2M to Platform devices
- Patches squashed:
dt-bindings: media: rkisp1: move rockchip-isp1 bindings out of staging
media: MAINTAINERS: rkisp1: add path to dt-bindings
media: rockchip: rkisp1: destage Rockchip ISP1 driver
media: MAINTAINERS: Update rkisp1 files with new location