API Change: TargetFrameLowering::eliminateCallFramePseudoInstr

Heads up for out-of-tree targets: in r265036,
TargetFrameLowering::eliminateCallFramePseudoInstr changed to return
an iterator to the next instruction, instead of returning void.

If your target was previously doing "MBB.erase(I); return;" your code
should now be doing "return MBB.erase(I);".

Thanks,
Hans