HPFS: Remove mark_inode_dirty

Remove mark_inode_dirty

HPFS doesn't use kernel's dirty inode indicator anyway because
writing an inode requires directory's mutex.

Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>