ar71xx: add support for TP-LINK TL-WR841N/ND v10

The TL-WR841N/ND v10 is mostly identical to the v9. Apart from some minor
changes, it contains a newer revision of the QCA9533 SoC and the CPU clock
is significantly higher.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

SVN-Revision: 47263