not working when CONFIG_TRACEFS_DISABLE_AUTOMOUNT enabled

[tiann]

when CONFIG_TRACEFS_DISABLE_AUTOMOUNT is enabled in kernel config, the kernel won't automount tracefs when mount debugfs, so the /sys/kernel/debug/tracing is not exist, we should use /sys/kernel/tracing instead.

Here is the kernel chanelog: https://osdn.net/projects/android-x86/scm/git/kernel/commits/412bd71850dbd2d78ee3bbd1e43e3ebe3c9bd819

And the mount:

oriole:/ # mount -t tracefs
tracefs on /sys/kernel/tracing type tracefs (rw,seclabel,relatime,gid=3012)

When we umount debugfs and remount, the /sys/kernel/debug/tracing is not exist, and we can't mount the tracefs to /sys/kernel/debug/tracing becase there isn't any mount point.

I replace all /sys/kernel/debug/tracing to /sys/kernel/tracing in the source code and compile it again can make it work.

[tiann]

#4046