ntfs: remove private wrapper of endian helpers

The base versions handle constant folding now and are shorter than these
private wrappers, use them directly.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>