dt-bindings: net: ti: add new cpsw switch driver bindings

Add bindings for the new TI CPSW switch driver. Comparing to the legacy
bindings (net/cpsw.txt):
- ports definition follows DSA bindings (net/dsa/dsa.txt) and ports can be
marked as "disabled" if not physically wired.
- all deprecated properties dropped;
- all legacy propertiies dropped which represent constant HW cpapbilities
(cpdma_channels, ale_entries, bd_ram_size, mac_control, slaves,
active_slave)
- TI CPTS DT properties are reused as is, but grouped in "cpts" sub-node
- TI Davinci MDIO DT bindings are reused as is, because Davinci MDIO is
reused.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>