dt-bindings: watchdog: sunxi: fix F1C100s compatible

The F1C100 series actually features a newer generation watchdog IP, so
the compatible string was wrong.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220317162349.739636-2-andre.przywara@arm.com