soc: spacemit: create a header for clock/reset registers

soc: spacemit: create a header for clock/reset registers

Move the definitions of register offsets and fields used by the SpacemiT
K1 SoC CCUs into a separate header file, so that they can be shared by
the reset driver that will be found under drivers/reset.

Signed-off-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Haylen Chu <heylenay@4d2.org>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20250702113709.291748-3-elder@riscstar.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>