mac80211: skip antenna gain when compiling regdb.txt (#15397)

The antenna gain attribute has been removed from the upstream regulatory database.
Incorperate patch from Luis R. Rodriguez to skip the parsing of the gain attribute
in genregdb.awk in order to emit proper rules again.

Also refresh fuzzy patches while we're at it.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

SVN-Revision: 40296