drivers/net/vsc9953: Use the generic Ethernet Switch parser

This patch replaces the parser used by VSC9953 L2 Switch driver with
the generic one. Also, the config macro that enables the
VSC9953 commands has been replaced in all the platforms that
use this driver with the config macro that corresponds to the
generic parser.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@freescale.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: York Sun <yorksun@freescale.com>