[RISCV] Use THShift_ri class instead of RVBShift_ri for TH_TST instruction. NFC

Author: topperc

llvm/lib/Target/RISCV/RISCVInstrInfoXTHead.td

@@ -270,7 +270,7 @@ def TH_REVW : THRev_r<0b10010, 0b00, "th.revw">;
 
 let Predicates = [HasVendorXTHeadBs], DecoderNamespace = "XTHeadBs",
     IsSignExtendingOpW = 1 in
-def TH_TST : RVBShift_ri<0b10001, 0b001, OPC_CUSTOM_0, "th.tst">,
+def TH_TST : THShift_ri<0b10001, 0b001, "th.tst">,
              Sched<[WriteSingleBitImm, ReadSingleBitImm]>;
 
 let Predicates = [HasVendorXTHeadCondMov] in {