i2c: riic: Pass IRQ desc array as part of OF data

i2c: riic: Pass IRQ desc array as part of OF data

In preparation for adding support for Renesas RZ/T2H and RZ/N2H SoCs,
which feature a combined error interrupt instead of individual error
interrupts per condition, update the driver to support configurable IRQ
layouts via OF data.

Introduce a new `irqs` field and `num_irqs` count in `riic_of_data` to
allow future SoCs to provide a custom IRQ layout. This patch is a
non-functional change for existing SoCs and maintains compatibility with
the current `riic_irqs` array.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com> # on RZ/A1
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250625104526.101004-4-prabhakar.mahadev-lad.rj@bp.renesas.com