[RISCV] Change type of Zicbop prefetch operand to GPRMem (llvm#139888)

Prior to this commit PREFETCH_* instructions considered their operand
register to be a simple GPR which is not entirely correct as it is a
base address for possible prefetching operation (According to cmobase
v1.0.1)

Author: arrv-sc

llvm/lib/Target/RISCV/RISCVInstrInfoZicbo.td

@@ -43,7 +43,7 @@ class CBO_r<bits<12> optype, string opcodestr>
 
 let hasSideEffects = 0, mayLoad = 1, mayStore = 1 in
 class Prefetch_ri<bits<5> optype, string opcodestr>
-    : RVInstS<0b110, OPC_OP_IMM, (outs), (ins GPR:$rs1, simm12_lsb00000:$imm12),
+    : RVInstS<0b110, OPC_OP_IMM, (outs), (ins GPRMem:$rs1, simm12_lsb00000:$imm12),
               opcodestr, "${imm12}(${rs1})"> {
   let Inst{11-7} = 0b00000;
   let rs2 = optype;