Revert "nptl i686: fix pthread_cond_wait.S compilation"

This reverts commit f71c0d8af11252f119fad04938ddd5501a7df21a.

libpthread/nptl/sysdeps/unix/sysv/linux/i386/i686/pthread_cond_wait.S

@@ -17,5 +17,4 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
-#undef __i686
 #include "../i486/pthread_cond_wait.S"