MAINTAINERS: Setup proper info for SOPHGO vendor support

Add git tree that maintaines sophgo vendor code.
Also replace Chao Wei with myself, since he does not have enough time.
Since sophgo vendor code is maintained, remove itself from
`RISC-V MISC SOC`

Acked-by: Chao Wei <chao.wei@sophgo.com>
Reviewed-by: Chen Wang <unicorn_wang@outlook.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/IA1PR20MB4953B158F6F575840F3D4267BB7D2@IA1PR20MB4953.namprd20.prod.outlook.com


Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>