irqchip/renesas-rzv2h: Add struct rzv2h_hw_info with t_offs variable

irqchip/renesas-rzv2h: Add struct rzv2h_hw_info with t_offs variable

The ICU block on the RZ/G3E SoC is almost identical to the one found on
the RZ/V2H SoC, with the following differences:

 - The TINT register base offset is 0x800 instead of zero.
 - The number of GPIO interrupts for TINT selection is 141 instead of 86.
 - The pin index and TINT selection index are not in the 1:1 map
 - The number of TSSR registers is 16 instead of 8
 - Each TSSR register can program 2 TINTs instead of 4 TINTs

Introduce struct rzv2h_hw_info to describe the SoC properties and refactor
the code by moving rzv2h_icu_init() into rzv2h_icu_init_common() and pass
the variable containing hw difference to support both these SoCs.

As a first step add t_offs to the new struct and replace the hardcoded
constants in the code.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Reviewed-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/all/20250224131253.134199-8-biju.das.jz@bp.renesas.com