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 --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6dee68d..ca1e091 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -310,7 +310,7 @@
 	 */
 	if (file) {
 		seq_pad(m, ' ');
-		seq_path(m, &file->f_path, "\n");
+		seq_file_path(m, file, "\n");
 		goto done;
 	}
 
@@ -1509,7 +1509,7 @@
 
 	if (file) {
 		seq_puts(m, " file=");
-		seq_path(m, &file->f_path, "\n\t= ");
+		seq_file_path(m, file, "\n\t= ");
 	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
 		seq_puts(m, " heap");
 	} else {