dt-bindings: soc: spacemit: define spacemit,k1-ccu resets

dt-bindings: soc: spacemit: define spacemit,k1-ccu resets

There are additional SpacemiT syscon CCUs whose registers control both
clocks and resets:  RCPU, RCPU2, and APBC2. Unlike those defined
previously, these will (initially) support only resets.  They do not
incorporate power domain functionality.

Previously the clock properties were required for all compatible nodes.
Make that requirement only apply to the three existing CCUs (APBC, APMU,
and MPMU), so that the new reset-only CCUs can go without specifying them.

Define the index values for resets associated with all SpacemiT K1
syscon nodes, including those with clocks already defined, as well as
the new ones (without clocks).

Signed-off-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20250702113709.291748-2-elder@riscstar.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>