[GlobalISel] findGISelOptimalMemOpLowering - remove dead initalization. NFCI.
[GlobalISel] findGISelOptimalMemOpLowering - remove dead initalization. NFCI.

Fixes static analyzer warning that "Value stored to 'NewTySize' during its initialization is never read".

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@371937 91177308-0d34-0410-b5e6-96231b3b80d8

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