drm: renesas: rz-du: mipi_dsi: Add OF data support

n preparation for adding support for the Renesas RZ/V2H(P) SoC, this patch
introduces a mechanism to pass SoC-specific information via OF data in the
DSI driver. This enables the driver to adapt dynamically to various
SoC-specific requirements without hardcoding configurations.

The MIPI DSI interface on the RZ/V2H(P) SoC is nearly identical to the one
on the RZ/G2L SoC. While the LINK registers are shared between the two
SoCs, the D-PHY registers differ. Also the VCLK range differs on both these
SoCs. To accommodate these differences `struct rzg2l_mipi_dsi_hw_info` is
introduced and as now passed as OF data.

These changes lay the groundwork for the upcoming RZ/V2H(P) SoC support by
allowing SoC-specific data to be passed through OF.

Co-developed-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20250609225630.502888-5-prabhakar.mahadev-lad.rj@bp.renesas.com