[AMDGPU] Fix typo in comment [NFC]

This replaces "V_MOB_B32" with "V_MOV_B32" in some comment.

llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp

@@ -893,7 +893,7 @@ bool GCNHazardRecognizer::fixVcmpxPermlaneHazards(MachineInstr *MI) {
     return false;
 
   // V_NOP will be discarded by SQ.
-  // Use V_MOB_B32 v?, v?. Register must be alive so use src0 of V_PERMLANE*
+  // Use V_MOV_B32 v?, v?. Register must be alive so use src0 of V_PERMLANE*
   // which is always a VGPR and available.
   auto *Src0 = TII->getNamedOperand(*MI, AMDGPU::OpName::src0);
   Register Reg = Src0->getReg();