swim: Add missing spinlock init

It doesn't seem this spinlock was properly initialized.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Finn Thain <fthain@telegraphics.com.au>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

drivers/block/swim.c

@@ -844,6 +844,7 @@ static int swim_floppy_init(struct swim_priv *swd)
 		swd->unit[drive].swd = swd;
 	}
 
+	spin_lock_init(&swd->lock);
 	swd->queue = blk_init_queue(do_fd_request, &swd->lock);
 	if (!swd->queue) {
 		err = -ENOMEM;