[rs6000] Remove inaccurate comment

DEBUG doesn't actually "replace abort with printf on error",
it just enables debugging output.  Just remove the comment.

[gcc/testsuite]

2018-10-29  Paul A. Clarke  <pc@us.ibm.com>

	* gcc.target/powerpc/ssse3-check.h: Remove inaccurate comment.

From-SVN: r265603

gcc/ChangeLog

+2018-10-29  Paul A. Clarke  <pc@us.ibm.com>
+
+	* gcc.target/powerpc/ssse3-check.h: Remove inaccurate comment.
+
 2018-10-29  Paul Koning  <ni1d@arrl.net>
 
 	* doc/rtl.texi (CONST_WIDE_INT_ELT): Give correct macro name.

gcc/testsuite/gcc.target/powerpc/ssse3-check.h

@@ -3,7 +3,6 @@
 
 #include "m128-check.h"
 
-/* define DEBUG replace abort with printf on error.  */
 //#define DEBUG 1
 
 #define TEST ssse3_test