tracing: Fix typoes in code comment and printk in trace_nop.c

tracing: Fix typoes in code comment and printk in trace_nop.c

echo nop > /sys/kernel/debug/tracing/options/current_tracer
echo 1 > /sys/kernel/debug/tracing/options/test_nop_accept
echo 0 > /sys/kernel/debug/tracing/options/test_nop_accept
echo 1 > /sys/kernel/debug/tracing/options/test_nop_refuse

Before the fix, the dmesg is a bit ugly since a align issue.

[  191.973081] nop_test_accept flag set to 1: we accept. Now cat trace_options to see the result
[  195.156942] nop_test_refuse flag set to 1: we refuse.Now cat trace_options to see the result

After the fix, the dmesg will show aligned log for nop_test_refuse and nop_test_accept.

[ 2718.032413] nop_test_refuse flag set to 1: we refuse. Now cat trace_options to see the result
[ 2734.253360] nop_test_accept flag set to 1: we accept. Now cat trace_options to see the result

Link: http://lkml.kernel.org/r/1457444222-8654-2-git-send-email-chuhu@redhat.com
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>