net: stmmac: Support devicetree configs for mcast and ucast filter entries

This patch adds and modifies code to support multiple Multicast and Unicast
Synopsys MAC filter configurations. The default configuration is defined to
support legacy driver behavior, which is 64 Multicast bins. The Unicast
filter code previously assumed all controllers support 32 or 16 Unicast
addresses based on controller version number, but this has been corrected
to support a default of 1 Unicast address. The filter configuration may
be specified through the devicetree using a Synopsys specific device tree
entry. This information was verified with Synopsys through
Synopsys Support Case #8000684337 and shared with the maintainer.

Signed-off-by: Vince Bridgers <vbridgers2013@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>