docs: netdev: document guidance on cleanup patches

The purpose of this section is to document what is the current practice
regarding clean-up patches which address checkpatch warnings and similar
problems. I feel there is a value in having this documented so others
can easily refer to it.

Clearly this topic is subjective. And to some extent the current
practice discourages a wider range of patches than is described here.
But I feel it is best to start somewhere, with the most well established
part of the current practice.
Signed-off-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241009-doc-mc-clean-v2-1-e637b665fa81@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/process/maintainer-netdev.rst

@@ -355,6 +355,8 @@ just do it. As a result, a sequence of smaller series gets merged quicker and
 with better review coverage. Re-posting large series also increases the mailing
 list traffic.
 
+.. _rcs:
+
 Local variable ordering ("reverse xmas tree", "RCS")
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -391,6 +393,21 @@ APIs and helpers, especially scoped iterators. However, direct use of
 ``__free()`` within networking core and drivers is discouraged.
 Similar guidance applies to declaring variables mid-function.
 
+Clean-up patches
+~~~~~~~~~~~~~~~~
+
+Netdev discourages patches which perform simple clean-ups, which are not in
+the context of other work. For example:
+
+* Addressing ``checkpatch.pl`` warnings
+* Addressing :ref:`Local variable ordering<rcs>` issues
+* Conversions to device-managed APIs (``devm_`` helpers)
+
+This is because it is felt that the churn that such changes produce comes
+at a greater cost than the value of such clean-ups.
+
+Conversely, spelling and grammar fixes are not discouraged.
+
 Resending after review
 ~~~~~~~~~~~~~~~~~~~~~~