[RISCV] Add break; to the last switch case

As suggested by jrtc27 in the post-commit review of D60528.

llvm-svn: 364746

Author: MaskRay

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -1761,6 +1761,7 @@ bool RISCVAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
   case RISCV::PseudoAddTPRel:
     if (checkPseudoAddTPRel(Inst, Operands))
       return true;
+    break;
   }
 
   emitToStreamer(Out, Inst);