[X86] concatSubVectors - remove unnecessary args. NFCI.
[X86] concatSubVectors - remove unnecessary args. NFCI.

All these args can be cheaply recomputed and it makes it much easier to use the function as a quick helper.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@367014 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm