(insv): Remove constraints from operand matching const_0_operand.

From-SVN: r2757

gcc/config/a29k/a29k.md

@@ -253,7 +253,7 @@
 (define_insn ""
   [(set (zero_extract:SI (match_operand:SI 0 "gpc_reg_operand" "+r")
 			 (const_int 16)
-			 (match_operand:SI 1 "const_0_operand" "I"))
+			 (match_operand:SI 1 "const_0_operand" ""))
 	(match_operand:SI 2 "cint_16_operand" "J"))]
   ""
   "consth %0,%m2")