MAINTAINERS: update nxp,imx8-jpeg.yaml reference

The file name: Documentation/devicetree/bindings/media/imx8-jpeg.yaml
should be, instead: Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml.

Update its cross-reference accordingly.

Fixes: be157db0 ("media: Add maintainer for IMX jpeg v4l2 driver")
Fixes: b16ed1e6 ("media: dt-bindings: Add bindings for i.MX8QXP/QM JPEG driver")
Reviewed-by: Mirela Rabulea <mirela.rabulea@nxp.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/70f3d37561b5ea4770a9f10c70ca2d29f99208b6.1634630486.git.mchehab+huawei@kernel.org