Remove some junk from HSAILSubtarget
Correct extra _s emitted before width in load / store
Don't emit _width(1)
Remove hasAddress / addressOpNum
Rename TypeLength operand to match spec
Use getNamedOperandIdx for width and type.
Rename $m operand to $mask.

This doesn't quite match the spec, but there seems to be a
terminology inconsistency between the existing code and the spec.
The spec for ld mentions a _const modifier and _width(n) modifiers,
but the code seems to look for "mask" which only means const.
Use getNamedOperandIdx for load modifier mask operand
Fix ubsan error in ValueMap
Copy getNamedOperand from R600
Add HSAILInstrInfo to BRIGAsmPrinter
Remove getValueType hack in HSAILTargetLowering

This isn't actually overriding anything now.
Remove unused functions
Use more named operand indices
Remove addressOpNum utility functions
Remove unused function