The new builtin-sprintf-warn-2.c xfail on line 83 and 84 for *-*-*-* which fails 
for arm-none-eabi for instance. The usual pattern for catchall xfail is *-*-*. 
This patch fixes the pattern as such.

ChangeLog entry is as follows:

*** gcc/testsuite/ChangeLog ***

2016-09-23  Thomas Preud'homme  <thomas.preudhomme@arm.com>

         * gcc.dg/tree-ssa/builtin-sprintf-warn-2.c: Fix xfail pattern.


Committing as obvious fix.

Best regards,

Thomas