ARM: dts: k2g: add dt bindings to support network driver

This patch add dt bindings to support network driver based on
Network Sub System (NSS) found on k2g SoC. This consists of
bindings for netcp node, nss qmss , pktdma, cpsw 2u version
of ethss and mdio.

In order to support transitioning between non-promiscuous
and promiscuous modes in K2G's ethernet switch, netcp ALE
needs to be enabled. Therefore this patch enables K2G's
netcp ALE for that purpose.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: WingMan Kwok <w-kwok2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>