perf trace beauty eventfd: No need to include eventfd.h

Old systems such as RHEL5 lack this file, and what we need is
already under ifdefs, so just ditch this #include.

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/trace/beauty/eventfd.c

···
-#include <sys/eventfd.h>
-
 #ifndef EFD_SEMAPHORE
 #define EFD_SEMAPHORE		1
 #endif