vfs: add seq_file_path() helper

Turn
	seq_path(..., &file->f_path, ...);
into
	seq_file_path(..., file, ...);

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --cc drivers/md/bitmap.c
Simple merge

diff --cc fs/proc/nommu.c
Simple merge

diff --cc fs/proc/task_mmu.c
Simple merge

diff --cc fs/proc/task_nommu.c
Simple merge

diff --cc fs/seq_file.c
Simple merge

diff --cc include/linux/seq_file.h
Simple merge

diff --cc mm/swapfile.c
Simple merge