encgen one scalable gpr, rexw only in env.mode=64
encgen one scalable gpr, rexw only in env.mode=64

Change-Id: I667f46650e5087206996cfd5dcc72cf8b8097d5c
(cherry picked from commit 4a6327103e4413a0b4483ea27c3929bd9a1c2a6d)

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