ir3/cp: Add missing const promotion check

We need to check the source type for moves when the destination type is
u16, just like the f16 check above.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13142>

src/freedreno/ir3/ir3_cp.c

@@ -428,6 +428,8 @@ reg_cp(struct ir3_cp_ctx *ctx, struct ir3_instruction *instr,
              */
             if (is_cat2_float(instr->opc) || is_cat3_float(instr->opc))
                return false;
+            if (instr->opc == OPC_MOV && type_float(instr->cat1.src_type))
+               return false;
          }
 
          src_reg = ir3_reg_clone(instr->block->shader, src_reg);