btrfs: tracepoints: add btrfs prefix to names where it's missing

btrfs: tracepoints: add btrfs prefix to names where it's missing

Most of our tracepoints have the 'btrfs_' prefix in their names but a few
of them are missing, making it inconsistent. So add the prefix to the ones
that are missing it, creating consistency, making it clear for users these
are btrfs tracepoints and eventually avoid name collisions with other
tracepoints defined by other kernel subsystems.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>