ath9k: add workaround for AR9331 USB host controller hang with USB1.1 devices

 When wifi radio is reset, some bits in (undocumented) USB registers may
 flip. Patch adds setting them after radio reset (channel change,
 up/down).
 With this patch stability of USB1.1 full-speed devices, connected
 directly to AR9331 host port (no USB2.0 hub) is improved.
Carambola2 doesn't use NVRAM, so NVRAM partition is not needed
carambola2: there is no reset button on GPIO12
opkg: update default carambola2 repo version
feeds: update, enable more kernel modules, packages. Reorganize .config

Move full config (with all packages in repo enabled) to 'config_full',
please copy it to '.config' when building all packages.
'.config' now contains minimal config to build only packages required by
firmware image. Should be easier starting point for new users.

Added routing and telephony feeds to feed config. Please uncomment them
when building from 'config_full'.
config: few packages were enabled (=y) by mistake in last commit
Fixes bug in texinfo for Debian builds
Merge remote-tracking branch 'upstream/master'