media: rcar-fcp: Update description for VIDEO_RENESAS_FCP Kconfig entry

The rcar-fcp driver is also used on Renesas RZ/G2 SoCs. Update the
Kconfig entry description to reflect this.

[hverkuil: incorporated Laurent's suggestions for subject and commit log]

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>