staging: fsl-dpaa2/ethsw: document nested structs as per kernel-doc

Document nested structs per kernel-doc requirements by moving
all comments before the actual struct.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>