ARM64: dts: amlogic: update serial aliases

Apparently, it's not valid to have an alias point to a disabled device.
Fix this by moving the aliases that are used (serial0) into the files
that use them, and remove aliases to disabled devices (serial1).

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>