Documenation: driver-api: fix gpio/board.rst warning

Fix markup warning: insert a blank line before the list.

Documentation/driver-api/gpio/board.rst:209: WARNING: Unexpected indentation.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/driver-api/gpio/board.rst

@@ -204,6 +204,7 @@ between a caller and a respective .get/set_multiple() callback of a GPIO chip.
 
 In order to qualify for fast bitmap processing, the array must meet the
 following requirements:
+
 - pin hardware number of array member 0 must also be 0,
 - pin hardware numbers of consecutive array members which belong to the same
   chip as member 0 does must also match their array indexes.