w1: w1_io.c: fix a kernel-doc warning

Add a blank line to avoid this Sphinx warning:
	./drivers/w1/w1_io.c:197: WARNING: Definition list ends without a blank line; unexpected unindent.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

drivers/w1/w1_io.c

@@ -194,6 +194,7 @@ static u8 w1_read_bit(struct w1_master *dev)
  *  bit 0 = id_bit
  *  bit 1 = comp_bit
  *  bit 2 = dir_taken
+ *
  * If both bits 0 & 1 are set, the search should be restarted.
  *
  * Return:        bit fields - see above