Added some notes about LLVM/clang patches
Added some notes about LLVM/clang patches

OpenISA/riscv-sbt,OpenISA/riscv-sbt,OpenISA/riscv-sbt,OpenISA/riscv-sbt,OpenISA/riscv-sbt,OpenISA/riscv-sbt,OpenISA/riscv-sbt