Documentation: fix some freescale dpio-driver.rst warnings

Fix markup warnings for one list by using correct list syntax.
Fix markup warnings for another list by using blank lines before the
list.

Documentation/networking/device_drivers/freescale/dpaa2/dpio-driver.rst:30: WARNING: Unexpected indentation.
Documentation/networking/device_drivers/freescale/dpaa2/dpio-driver.rst:143: WARNING: Unexpected indentation.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Stuart Yoder <stuyoder@gmail.com>
Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Cc: netdev@vger.kernel.org
Cc: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>