ARM: dts: r8a7742-iwg21d-q7-dbcm-ca: Add support for 8-bit ov7725 sensors

ARM: dts: r8a7742-iwg21d-q7-dbcm-ca: Add support for 8-bit ov7725 sensors

The 8-bit ov7725 sensors can also be connected to the camera daughter
board.

This patch creates a separate dtsi file to describe an ov7725 sensor,
and includes it multiple times in r8a7742-iwg21d-q7-dbcm-ca.dts. The
user can (un)comment #include statements depending on the cameras
connected.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
[geert: describe a single camera in the .dtsi, include multiple times]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20210122113424.2833127-3-geert+renesas@glider.be