include/: ignore new sys/eventfd.h symlink

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

include/.gitignore

@@ -26,6 +26,7 @@
 /sys/debugreg.h
 /sys/elf.h
 /sys/epoll.h
+/sys/eventfd.h
 /sys/fpregdef.h
 /sys/inotify.h
 /sys/io.h