rt2x00 : RT3290 chip support v4

This patch support the new chipset rt3290 wifi implementation in rt2x00.
It initailize the related mac, bbp and rf register in startup phase.
And this patch modify the efuse read/write method for the different efuse data offset of rt3290.

Signed-off-by: Woody Hung <Woody.Hung@mediatek.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>