riscv: dts: spacemit: adapt regulator node name to preferred form

riscv: dts: spacemit: adapt regulator node name to preferred form

The preferred node name for fixed-regulators has changed to pattern [1]:
 '^regulator(-[0-9]+v[0-9]+|-[0-9a-z-]+)?$'

Adjust all SpacemiT DT regulator node names to fix this.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20240426215147.3138211-1-robh@kernel.org
Link: https://lore.kernel.org/r/20260226-02-k1-regulator-names-v1-1-e87695d50159@kernel.org
Signed-off-by: Yixun Lan <dlan@kernel.org>