doc: t1040-l2switch: Update README

The driver for VSC9953 L2 switch IP supports many features and
the documentation needs to be updated.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@freescale.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
1 file changed