arm: dts: mt7623: add missing pause for switchport

port6 of mt7530 switch (= cpu port 0) on bananapi-r2 misses pause option
which causes rx drops on running iperf.

Fixes: f4ff257c

 ("arm: dts: mt7623: add support for Bananapi R2 (BPI-R2) board")
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200907070517.51715-1-linux@fw-web.de
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>