[COFF, ARM64] Fix typo in COFF ARM64 Relocation Type
[COFF, ARM64] Fix typo in COFF ARM64 Relocation Type

Summary:
Fixed IMAGE_REL_ARM64_PAGEBASE_REL2 ==> IMAGE_REL_ARM64_PAGEBASE_REL21
Refer: http://www.microsoft.com/whdc/system/platform/firmware/PECOFF.mspx

Reviewers: zturner, rnk, ruiu

Reviewed By: ruiu

Subscribers: aemerson, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D34659

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@306366 91177308-0d34-0410-b5e6-96231b3b80d8

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