Add member EmitNOAT and its setter and getter functions to class MipsFunctionInfo. If EmitNOAT is true, directives ".set noat" and ".set at" are emitted at the beginning and end of a function. 
Add member EmitNOAT and its setter and getter functions to class MipsFunctionInfo.
If EmitNOAT is true, directives ".set noat" and ".set at" are emitted at the
beginning and end of a function. 



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@153528 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,chubbymaggie/asap,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,chubbymaggie/asap,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,chubbymaggie/asap,dslab-epfl/asap,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,dslab-epfl/asap,dslab-epfl/asap,chubbymaggie/asap,chubbymaggie/asap,dslab-epfl/asap,llvm-mirror/llvm,dslab-epfl/asap,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,apple/swift-llvm,dslab-epfl/asap,chubbymaggie/asap,GPUOpen-Drivers/llvm