dts: wch: move ch32v00x.dtsi to ch32v0/ch32v003.dtsi

The CH32V003 belongs to the CH32V0 series. To improve code organization
and maintainability, all related files should be grouped together in a
dedicated subdirectory.

Signed-off-by: Jianxiong Gu <jianxiong.gu@outlook.com>