docs: net: dpio-driver.rst: fix two codeblock warnings

    Documentation/networking/device_drivers/freescale/dpaa2/dpio-driver.rst:43: WARNING: Definition list ends without a blank line; unexpected unindent.
    Documentation/networking/device_drivers/freescale/dpaa2/dpio-driver.rst:63: WARNING: Unexpected indentation. looking for now-outdated files... none found

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>