VideoSoftware: remove duplicated CommandProcessor structures.

No functional change; the structs/enums are identical.
Can we maybe do a `using CommandProcessor::UCPStatusReg = UCPStatusReg` here, and similarly for the other CP structs? Seems weird having to use `CommandProcessor::UCPStatusReg` within a SWCommandProcessor namespace when there's no `SWCommandProcessor::UCPStatusReg` anyway.