fat: Fix stat->f_namelen

I found that the length of a file name when created cannot exceed 255
characters, yet, pathconf(), via statfs(), returns the maximum as 260.

Signed-off-by: Kevin Dankwardt <k@kcomputing.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 14da530..d0a504c 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -558,7 +558,7 @@
 	buf->f_bavail = sbi->free_clusters;
 	buf->f_fsid.val[0] = (u32)id;
 	buf->f_fsid.val[1] = (u32)(id >> 32);
-	buf->f_namelen = sbi->options.isvfat ? 260 : 12;
+	buf->f_namelen = sbi->options.isvfat ? FAT_LFN_LEN : 12;
 
 	return 0;
 }