reset: spacemit: add support for SpacemiT CCU resets

reset: spacemit: add support for SpacemiT CCU resets

Implement reset support for SpacemiT CCUs.  A SpacemiT reset controller
device is an auxiliary device associated with a clock controller (CCU).

This patch defines the reset controllers for the MPMU, APBC, and MPMU
CCUs, which already define clock controllers.  It also adds RCPU, RCPU2,
and ACPB2 CCUs, which only define resets.

Signed-off-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20250702113709.291748-6-elder@riscstar.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>