'fat.h' includes <linux/buffer_head.h> which includes <linux/fs.h> which
includes all the header files required for all *.c files fat filesystem.

[akpm@linux-foundation.org: fs/fat/iode.c needs seq_file.h]
[sfr@canb.auug.org.au: put one actually necessary include file back]
Signed-off-by: NAlexander Kuleshov <kuleshovmail@gmail.com>
Acked-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>