[AMDGPU] Fix latency for implicit vcc_lo operands on GFX10 wave32

As described in the comment, the way we change vcc to vcc_lo in these
operands confuses addPhysRegDataDeps into treating them as implicit
pseudo operands. Fix this by setting the correct latency from the
SchedModel after addPhysRegDataDeps wrongly set it to 0.

Differential Revision: https://reviews.llvm.org/D112317