watchdog: rzg2l_wdt: Add rzv2m support

The WDT on RZ/V2M devices is basically the same as RZ/G2L, but without
the parity error registers. This means the driver has to reset the
hardware plus set the minimum timeout in order to do a restart and has
a single interrupt.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220823093233.8577-3-phil.edworthy@renesas.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>