fs/ntfs3: Avoid possible memory leak

smatch warn:
fs/ntfs3/fslog.c:2172 last_log_lsn() warn: possible memory leak of 'page_bufs'
Jump to label 'out' to free 'page_bufs' and is more consistent with
other code.

Signed-off-by: Su Hui <suhui@nfschina.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>