Merge branch 'devlink-param-type-string-fixes'

Moshe Shemesh says:

====================
devlink param type string fixes

This patchset fixes devlink param infrastructure for string param type.

The devlink param infrastructure doesn't handle copying the string data
correctly.  The first two patches fix it and the third patch adds helper
function to safely copy string value without exceeding
DEVLINK_PARAM_MAX_STRING_VALUE.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>