Currently dpaa2_switch_takedown has a funny name and does not do the
opposite of dpaa2_switch_init, which makes probing fail when we need to
handle an -EPROBE_DEFER.

A sketch of what dpaa2_switch_init does:

	dpsw_open

	dpaa2_switch_detect_features

	dpsw_reset

	for (i = 0; i < ethsw->sw_attr.num_ifs; i++) {
		dpsw_if_disable

		dpsw_if_set_stp

		dpsw_vlan_remove_if_untagged

		dpsw_if_set_tci

		dpsw_vlan_remove_if
	}

	dpsw_vlan_remove

	alloc_ordered_workqueue

	dpsw_fdb_remove

	dpaa2_switch_ctrl_if_setup

When dpaa2_switch_takedown is called from the error path of
dpaa2_switch_probe(), the control interface, enabled by
dpaa2_switch_ctrl_if_setup from dpaa2_switch_init, remains enabled,
because dpaa2_switch_takedown does not call
dpaa2_switch_ctrl_if_teardown.

Since dpaa2_switch_probe might fail due to EPROBE_DEFER of a PHY, this
means that a second probe of the driver will happen with the control
interface directly enabled.

This will trigger a second error:

[   93.273528] fsl_dpaa2_switch dpsw.0: dpsw_ctrl_if_set_pools() failed
[   93.281966] fsl_dpaa2_switch dpsw.0: fsl_mc_driver_probe failed: -13
[   93.288323] fsl_dpaa2_switch: probe of dpsw.0 failed with error -13

Which if we investigate the /dev/dpaa2_mc_console log, we find out is
caused by:

[E, ctrl_if_set_pools:2211, DPMNG]  ctrl_if must be disabled

So make dpaa2_switch_takedown do the opposite of dpaa2_switch_init (in
reasonable limits, no reason to change STP state, re-add VLANs etc), and
rename it to something more conventional, like dpaa2_switch_teardown.

Fixes: 613c0a58 ("staging: dpaa2-switch: enable the control interface")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20210819141755.1931423-1-vladimir.oltean@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>