R600: Do not fold modifier/litterals in vector inst

This fixes a couple of regressions on (probably not just) cayman

NOTE: This is a candidate for the Mesa stable branch.

Reviewed-by: Tom Stellard <thomas.stellard at amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175180 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Fold zero/one in export instructions

Reviewed-by: Tom Stellard <thomas.stellard at amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175181 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Export instructions are no longer terminator

This allows MachineInstScheduler to reorder them, and thus make scheduling more
efficient.

Reviewed-by: Tom Stellard <thomas.stellard at amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175182 91177308-0d34-0410-b5e6-96231b3b80d8