dpaa2-switch: add support for port mirroring

Add support for per port mirroring for the DPAA2 switch. We support
only single mirror port, therefore we allow mirroring rules only as long
as the destination port is always the same.

Unlike all the actions (drop, redirect, trap) already supported by the
dpaa2-switch driver, adding mirroring filters in shared blocks is not
achieved by a singular ACL entry added in a table shared by the ports.
This is why, when a new mirror filter is added in a block we have to got
through all the switch ports sharing it and configure the filter
individually on all.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>