staging: fsl-dpaa2/ethsw: remove unused structure

The dpsw_cfg structure is only used when creating a new dpsw DPAA2
object. In the DPAA2 architecture, objects are created at boot time by
the firmware or dynamically from userspace while drivers on the fsl-mc
bus only configure those objects.
Remove the structure since it's of no use.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/1564416712-16946-2-git-send-email-ioana.ciornei@nxp.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>