ar71xx-mikrotik: remove kmod-ath5k package

ath5k supports only IEEE 802.11 a/b/g

Signed-off-by: Matthias Fritzsche <matthias@chemnitz.freifunk.net>

targets/ar71xx-mikrotik

 config 'CONFIG_GLUON_SPECIALIZE_KERNEL=y'
 
-# Enable ath5k in addition to ath9k
-# ath5k cards are commonly used with Mikrotik hardware
-packages 'kmod-ath5k'
-
 device mikrotik-rb-nor-flash-16M rb-nor-flash-16M
 factory