ath9k expects to get revision id 2 for the QCA9531 ver. 2 rev. 0. This
fixes the very low TX power on some devices like the TP-LINK
TL-WR841ND v10.

As ath79_soc_rev is only used to get the revision number to ath9k on the
QCA9533, just set it to the expected value on the ver. 2.

Some more cleanup.

This patch adds the kernel modules to for the very common Realtek RTL8150 and Realtek 8152 based USB-to-Ethernet converters.
After this patch the following packages can be added to targets (or site.mk):
kmod-usb-net-rtl8150
kmod-usb-net-rtl8152

The modules are already available in openwrt trunk, but not in Chaos Calmer. This patch is just a temporary backport.
The modules are needed for Futros with additional USB-Ethernet-Interface and VMs with dedicated USB-NIC

This reverts commit 8ad3c881.

We can't use the same image for these two devices, so as a workaround,
remove ZR-600DHP from the name for now, so the autoupdater can work and
users aren't confused.

This also takes us past the OpenWrt 15.05 final release.

This reverts commit 91b3c1d3.

This reverts commit 6da1677d.

Fixes site.conf checks.

This might improve stability on the TL-WR841 v9.

hostapd would switch the primary and secondary channel on 5GHz networks in
certain circumstances, completely breaking the adhoc interfaces of the WLAN
adapter (they would lose their configuration).

As a temporary fix, disable this channel switch function.

Original patch by @MPW1412

The TL-WR741ND will identify itself as a TL-WR740N/ND as well. This is fine as
the images are identical anyways.

Recent changes in the routing configuration of OpenWrt broke source address
selection, sometimes leading to the node trying to contact other addresses in
the mesh network from the next-node address.

Revert the problematic commits until this has been solved upstream.