[X86] Use X86ISD::MUL_IMM instead of ISD::MUL for multiply we intend to be selected to LEA.
[X86] Use X86ISD::MUL_IMM instead of ISD::MUL for multiply we intend to be selected to LEA.

This prevents other combines from possibly disturbing it.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@337890 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm