ath79: mikrotik: stack ar9344 devices to single dtsi

ath79: mikrotik: stack ar9344 devices to single dtsi

Most of boards from MikroTik with AR9344 SoC (supported and
un-supported) replicate the same schematic, so stack common device nodes
to a single dtsi.

ar9344_mikrotik_routerboard-16m-nor.dtsi:
- remove include paragraph and wmac node, make it single nor flash node
  for others dts to include

ar9344_mikrotik_routerboard-lhg-5nd.dts:
- move all of the nodes to new file ar9344_mikrotik_routerboard.dtsi
  and leave only power, user and lan LEDs which differ from sxt-5nd-r2
  and other yet unsupported devices

ar9344_mikrotik_routerboard-sxt-5n.dtsi:
- remove, it made no sense to keep it, as only
  ar9344_mikrotik_routerboard-sxt-5nd-r2.dts included this file and
  added only compatible and model

ar9344_mikrotik_routerboard-sxt-5nd-r2.dts:
- include ar9344_mikrotik_routerboard.dtsi
- add nand gpio activating node, beeper, additional LEDs and flash chips
  which previously have been in ar9344_mikrotik_routerboard-sxt-5n.dtsi

ar9344_mikrotik_routerboard.dtsi:
- inherited most of the content from ar9344_mikrotik_routerboard-lhg-5nd.dts
  except three LEDs
- add wmac node, removed from ar9344_mikrotik_routerboard-16m-nor.dtsi

Signed-off-by: Tomasz Maciej Nowak <tmn505@gmail.com>