clk: renesas: rzg2l: Remove DSI clock rate restrictions

clk: renesas: rzg2l: Remove DSI clock rate restrictions

Convert the limited MIPI clock calculations to a full range of settings
based on math including H/W limitation validation.
Since the required DSI division setting must be specified from external
sources before calculations, expose a new API to set it.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Tested-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20251124131003.992554-2-chris.brandt@renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>