pinctrl: renesas: rzg2l: Allow more bits for pin configuration

pinctrl: renesas: rzg2l: Allow more bits for pin configuration

The pin configuration bits have been growing for every new SoCs being
added for the pinctrl-rzg2l driver which would mean updating the macros
every time for each new configuration.  To avoid this allocate additional
bits for pin configuration by relocating the known fixed bits to the very
end of the configuration.

Also update the size of 'cfg' to 'u64' to allow more configuration bits
in the 'struct rzg2l_variable_pin_cfg'.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> # on RZ/G3S
Link: https://lore.kernel.org/r/20240530173857.164073-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>