ffs_alloc_dev and ffs_free_dev are used only in f_fs.c,
so make them static.
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NAndrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>