Fix printing of f16 machine operands
Fix printing of f16 machine operands

Only single and double FP immediates are correctly printed by
MachineInstr::print() during debug output. Half float type goes to
APFloat::convertToDouble() and hits assertion it is not a double
semantics. This diff prints half machine operands correctly.

This cannot currently be hit by any in-tree target.

Patch by Stanislav Mekhanoshin

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@259857 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm