Fix FIXME for M68k::MOV16dc

[JomerDev]

There is a FIXME here for the MOVE from CCR instruction on 68000. From my understanding the way to fix it would be to use MOVE from SR instead, since CCR is just the lower byte of SR.
I looked at the code in an attempt to fix it myself but after trying to find a way for some time I just have no idea where to get the information from if the target is 68000 or 68010 in or around that function, so this is the best I can do right now

[llvmbot]

@llvm/issue-subscribers-backend-m68k

Author: Jomer (JomerDev)

There is a FIXME [here](https://github.com/llvm/llvm-project/blob/main/llvm/lib/Target/M68k/M68kInstrInfo.cpp#L497) for the `MOVE from CCR` instruction on 68000. From my understanding the way to fix it would be to use `MOVE from SR` instead, since CCR is just the lower byte of SR. I looked at the code in an attempt to fix it myself but after trying to find a way for some time I just have no idea where to get the information from if the target is 68000 or 68010 in or around that function, so this is the best I can do right now

[tclin914]

I think it can call Subtarget.atLeastM68010() to get the cpu information.