nfp: fix the access to management firmware hanging

When running `ethtool -p` with the old management firmware,
the management firmware resource is not correctly released,
which causes firmware related malfunction: all the access
to management firmware hangs.

It releases the management firmware resource when set id
mode operation is not supported.

Fixes: ccb9bc1d

 ("nfp: add 'ethtool --identify' support")
Signed-off-by: Gao Xiao <gao.xiao@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Link: https://lore.kernel.org/r/20220829101651.633840-1-simon.horman@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>