docs: hwmon: mp2975.rst: address some html build warnings

docs: hwmon: mp2975.rst: address some html build warnings

    .../Documentation/hwmon/mp2975.rst:25: WARNING: Unexpected indentation.
    .../Documentation/hwmon/mp2975.rst:27: WARNING: Block quote ends without a blank line; unexpected unindent.
    .../Documentation/hwmon/mp2975.rst:69: WARNING: Unexpected indentation.
    .../Documentation/hwmon/mp2975.rst:70: WARNING: Block quote ends without a blank line; unexpected unindent.
    .../Documentation/hwmon/mp2975.rst:72: WARNING: Bullet list ends without a blank line; unexpected unindent.
    .../Documentation/hwmon/mp2975.rst: WARNING: document isn't included in any toctree

List blocks should have blank lines before and after them,
in order to be properly parsed.

Fixes: 4beb7a028e9f ("hwmon: (pmbus) Add support for MPS Multi-phase mp2975 controller")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/b02f98d886ab1f5af233f8999c7a15529fc52cdc.1603791716.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>