enc2gen: add vsib index width to opnd sig for sparse ops
enc2gen: add vsib index width to opnd sig for sparse ops

Change-Id: I5e0accae3cb1186a00d42d04be96ed3fc308cebf
(cherry picked from commit 57c28e983098bdabb109c23af16b4c28325a2ab0)

intelxed/xed,intelxed/xed,intelxed/xed,intelxed/xed