Naming in code comments for tracing_snapshot, tracing_snapshot_alloc
and trace_pid_filter_add_remove_task don't match the real function
names.  And latency_trace has been removed from tracing directory.
Fix them.

Link: http://lkml.kernel.org/r/1508394753-20887-1-git-send-email-chuhu@redhat.com

Fixes: cab50379 ("tracing/ftrace: Enable snapshot function trigger")
Fixes: 886b5b73 ("tracing: remove /debug/tracing/latency_trace")
Signed-off-by: NChunyu Hu <chuhu@redhat.com>
[ Replaced /sys/kernel/debug/tracing with /sys/kerne/tracing ]
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>