nv50/ir: replace zeros in movs as well

The original change to put zeroes directly into instructions created
conditional mov's with the zero immediate. However that can't be
emitted, so make sure to replace the zero with r63.

Fixes: 52a800a68 (nv50/ir: allow immediate 0 to be loaded anywhere)
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nv50.cpp

@@ -293,8 +293,7 @@ NV50LegalizePostRA::visit(BasicBlock *bb)
                next = hi;
          }
 
-         if (i->op != OP_MOV && i->op != OP_PFETCH &&
-             i->op != OP_BAR &&
+         if (i->op != OP_PFETCH && i->op != OP_BAR &&
              (!i->defExists(0) || i->def(0).getFile() != FILE_ADDRESS))
             replaceZero(i);
       }