dt-bindings: net: dsa: fix typos in bindings docs

Fix "alway" -> "always" in lan9303.txt and marvell,mv88e6xxx.yaml.

Signed-off-by: Akiyoshi Kurita <weibu@redadmin.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260123150211.2646235-1-weibu@redadmin.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>