BugLink: https://bugs.launchpad.net/bugs/1864775

commit 7980dff3 upstream.

Add a missing property to GMAC node so that multicast filtering works
correctly.

Fixes: 556cc1c5 ("ARC: [axs101] Add support for AXS101 SDP (software development platform)")
Acked-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>