Fix error format string.

gcc/ChangeLog:

2020-03-06  Andreas Krebbel  <krebbel@linux.ibm.com>

	* config/s390/s390.md ("tabort"): Get rid of two consecutive
	blanks in format string.

gcc/config/s390/s390.md

@@ -11931,8 +11931,8 @@
   if (CONST_INT_P (operands[0])
       && INTVAL (operands[0]) >= 0 && INTVAL (operands[0]) <= 255)
     {
-      error ("invalid transaction abort code: %wd;  values in range 0 "
-	     "through 255 are reserved", INTVAL (operands[0]));
+      error ("invalid transaction abort code: %wd (values in range 0 "
+	     "through 255 are reserved)", INTVAL (operands[0]));
       FAIL;
     }
 })