[mips] Hoist common functionality into a new function.      Given that we support multiple directives that enable a particular feature (e.g. '.set mips16'), it's best to hoist that code into a new function so that we don't repeat the same pattern w.r.t parsing and handling error cases.
[mips] Hoist common functionality into a new function.
    
Given that we support multiple directives that enable a particular feature
(e.g. '.set mips16'), it's best to hoist that code into a new function
so that we don't repeat the same pattern w.r.t parsing and handling error cases.

No functional changes.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@204811 91177308-0d34-0410-b5e6-96231b3b80d8

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