rt2x00: Fix RF3052 channel initialization

Update channel initialization for the RF3052 chipset.
According to the Ralink drivers, the rt3x array must be
used for this chipset, rather then the rt2x array.

Furthermore RF3052 supports the 5GHz band, extend
the rt3x array with the 5GHz channels, and use them
for the RF3052 chip.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>