Add <imp-def> and <imp-kill> operands when replacing virtual sub-register defs and kills.

An instruction like this:

  %reg1097:1<def> = VMOVSR %R3<kill>, 14, %reg0

Must be replaced with this when substituting physical registers:

  %S0<def> = VMOVSR %R3<kill>, 14, %reg0, %D0<imp-def>

llvm-svn: 92812