arm64: dts: apple: change ethernet0 device type to ethernet

Fixes make dtbs_check errors for t8103-j274.dts due to missing pci
properties.

Fixes: e1bebf97 ("arm64: dts: apple: j274: Expose PCI node for the Ethernet MAC address")
Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
Signed-off-by: Janne Grunau <j@jannau.net>
Tested-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>