treewide: mark devices as BROKEN instead of commenting out

treewide: mark devices as BROKEN instead of commenting out

This adds the newly introduced BROKEN flag to a bunch of devices
that previously just had TARGET_DEVICES commented out. By this, we
can select them in make menuconfig when BROKEN developer config option
is selected, instead of having to edit the code.

In contrast to DEFAULT := n, this is meant to cover devices that
don't boot or don't compile at all.

ath25: np25g, wpe53g
  both disabled during kernel bump 3.18->4.4 without reason given
  f89a20a89aeb ("ath25: update kernel from 3.18 to 4.4")

bcm53xx: linksys-ea6300-v1, linksys-ea9200, linksys-ea9500
  broken due to insufficient/broken TRX support
  55ff15cfd509 ("bcm53xx: disable building Linksys EA6300 V1 image")
  cd0f9900a4cd ("bcm53xx: parepare for building more Linksys images")

bcm63xx: tplink-archer-c5-v2, tplink-archer-c9-v1
  disabled when kernel 5.4 support was added, probably broken
  50c6938b95a0 ("bcm53xx: add v5.4 support")

Signed-off-by: Petr Štetiar <ynezz@true.cz>
[limit to subset of devices, use BROKEN, adjust commit message/title]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>