ramips: update ZBT WE1026 DTS-files

ramips: update ZBT WE1026 DTS-files

This commit makes the following changes to the WE1026 DTS-files:

* The parts that are unique to the -5G-version (LED and 5GHz wifi)
are moved to a separate file, so that WE1026.dtsi can be referenced also
by the DTS for the -H version.
* Use the generic "flash"-name for the spi-nor node.
* Add label MAC.

All changes have been tested on the WE1026-5G-16M and work fine. I.e.,
the device works as before the DTS-changes.

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Acked-by: Mathias Kresin <dev@kresin.me>
Acked-by: Alex Maclean <monkeh@monkeh.net>
Acked-by: INAGAKI Hiroshi <musashino.open@gmail.com>
Acked-by: Petr Štetiar <ynezz@true.cz>
[minor style fixes, rebased onto base-files split, remove obsolete
gpio-keys comment]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>