[RISCV] Recognize new relocation types
[RISCV] Recognize new relocation types

This patch adds all RISC-V relocation types, as of binutils 2.29. Note that 
R_RISCV32_PCREL is not currently documented in the RISC-V ELF PSABI.

Differential Revision: https://reviews.llvm.org/D36455

Patch by Chih-Mao Chen (@PkmX)


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@310914 91177308-0d34-0410-b5e6-96231b3b80d8

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