dt-bindings: soc: renesas: mfis: Add R-Car V4H/V4M support

dt-bindings: soc: renesas: mfis: Add R-Car V4H/V4M support

The above SoCs have only 12 mailboxes and do not have an extra register
space for mailboxes.  Everything is contained in the common register
set.  In addition to adding these SoCs, the other entries get updated to
enforce 2 register spaces and their specific number of interrupts.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260519075620.4128-2-wsa+renesas@sang-engineering.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>