MAINTAINERS: Merge DART into ARM/APPLE MACHINE

It's the same people anyway.

Signed-off-by: Sven Peter <sven@svenpeter.dev>
Acked-by: Hector Martin <marcan@marcan.st>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Link: https://lore.kernel.org/r/20220412161211.23162-1-sven@svenpeter.dev
Signed-off-by: Joerg Roedel <jroedel@suse.de>