[SLP] use range-for loops, fix formatting; NFC
[SLP] use range-for loops, fix formatting; NFC

These are part of D57059, but that patch doesn't apply cleanly to trunk
at this point, so we might as well remove some of the noise.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@369776 91177308-0d34-0410-b5e6-96231b3b80d8

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