tracing/events: simplify system_enable_read()
tracing/events: simplify system_enable_read()

A smarter way to figure out the output of an enable file.

[ Impact: clean up ]

Signed-off-by: Li Zefan <5dc16b054e85ffba6c8d314d8e55ae95dcab12a5@cn.fujitsu.com>
Acked-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>
Acked-by: Frederic Weisbecker <e8a1bf9163cb25e93cfd6540f223b3872ea7ee55@gmail.com>
LKML-Reference: <17e4e665e77dce1302234439e4dad837461b81b7@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@elte.hu>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs