[AMDGPU] Encode NV bit in VIMAGE/VSAMPLE. NFC (#153654)

This is NFC as this target does not have it.

Author: rampitec

llvm/lib/Target/AMDGPU/SIInstrFormats.td

@@ -473,6 +473,7 @@ class VIMAGE_VSAMPLE_Common <bits<8> op> : Enc96 {
   let Inst{4} = r128;
   let Inst{5} = d16;
   let Inst{6} = a16;
+  let Inst{7} = cpol{5}; // nv
   let Inst{21-14} = op;
   let Inst{25-22} = dmask;
   let Inst{39-32} = vdata;