x86: Fix assembler for Pextr
x86: Fix assembler for Pextr

Pextr family instructions use r/m part of rmod byte as destination.
This should be handled appropriately.
Disassembler works correctly.

Change-Id: I89d00cb11ae792e9d28c178ba79a0bc1fa27e3c5
Signed-off-by: Serguei Katkov <53c1eb3349c33a81de4c7fece05dd168a3eb410e@intel.com>

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst