ARM: dts: BCM5301X: Add DT for ASUS RT-AC3100

ARM: dts: BCM5301X: Add DT for ASUS RT-AC3100

ASUS RT-AC3100 is ASUS RT-AC88U without the external switch. Move the
shared bindings to bcm47094-asus-rt-ac3100.dtsi.

Remove the fixed-link node on port@7 as commit ba4aebce23b2 ("ARM: dts:
BCM5301X: Describe switch ports in the main DTS") states it's not
necessary.

Replace the copyright notice with an author notice.

Rename the model name from Asus to ASUS on bcm47094-asus-rt-ac88u.dts.

Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230803071454.5902-2-arinc.unal@arinc9.com
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>