R600: Change UDIV/UREM to UDIVREM when legalizing types

When legalizing ops, with UDIV/UREM set to expand, they automatically
expand to UDIVREM (if legal or custom).
We need to do this manually for legalize types.

v2:
  SI should be set to Expand because the type is legal, and it is
    automatically lowered to UDIVREM if UDIVREM is Legal/Custom
  R600 should set to UDIV/UREM to Custom because it needs to lower them
    during type legalization

Patch by: Jan Vesely

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
llvm-svn: 207587