arm64: dts: apple: t8103: Disable unused PCIe ports

The PCIe ports are unused (without devices) so disable them instead of
removing them.

Fixes: 7c77ab91 ("arm64: dts: apple: Add missing M1 (t8103) devices")
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Hector Martin <marcan@marcan.st>