nilfs2: use mark_buffer_dirty to mark btnode or meta data dirty

This replaces nilfs_mdt_mark_buffer_dirty and nilfs_btnode_mark_dirty
macros with mark_buffer_dirty and gets rid of nilfs_mark_buffer_dirty,
an own mark buffer dirty function.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

diff --cc fs/nilfs2/alloc.c
Simple merge

diff --cc fs/nilfs2/btnode.c
Simple merge

diff --cc fs/nilfs2/btnode.h
Simple merge

diff --cc fs/nilfs2/btree.c
Simple merge

diff --cc fs/nilfs2/cpfile.c
Simple merge

diff --cc fs/nilfs2/dat.c
Simple merge

diff --cc fs/nilfs2/gcinode.c
Simple merge

diff --cc fs/nilfs2/ifile.c
Simple merge

diff --cc fs/nilfs2/inode.c
Simple merge

diff --cc fs/nilfs2/mdt.c
Simple merge

diff --cc fs/nilfs2/mdt.h
Simple merge

diff --cc fs/nilfs2/page.c
Simple merge

diff --cc fs/nilfs2/page.h
Simple merge

diff --cc fs/nilfs2/segment.c
Simple merge

diff --cc fs/nilfs2/sufile.c
Simple merge