arm64: dts: renesas: rzg2ul-smarc-som: Drop enabling wdt2

WDT CH2 is specifically to check the operation of Cortex-M33 CPU so
don't enable WDT2 by default.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20220914134211.199631-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>