rt2x00: Implement support for rt2800usb

Add support for the rt2800usb chipset.

Current problems:
 * Cannot scan 11n AP's
 * No TX during first minute after association
 * Broken Hardware encryption

Includes various patches from Mattias, Felix, Xose and Axel.
Signed-off-by: Mattias Nissler <mattias.nissler@gmx.de>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Signed-off-by: Axel Kollhofer <rain_maker@root-forum.org>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/Kconfig

@@ -77,6 +77,20 @@ config RT73USB
 
 	  When compiled as a module, this driver will be called "rt73usb.ko".
 
+config RT2800USB
+	tristate "Ralink rt2800 (USB) support"
+	depends on USB
+	select RT2X00_LIB_USB
+	select RT2X00_LIB_HT
+	select RT2X00_LIB_FIRMWARE
+	select RT2X00_LIB_CRYPTO
+	select CRC_CCITT
+	---help---
+	  This adds support for rt2800 wireless chipset family.
+	  Supported chips: RT2770, RT2870 & RT3070.
+
+	  When compiled as a module, this driver will be called "rt2800usb.ko".
+
 config RT2X00_LIB_PCI
 	tristate
 	select RT2X00_LIB

drivers/net/wireless/rt2x00/Makefile

@@ -18,3 +18,4 @@ obj-$(CONFIG_RT2500PCI)			+= rt2500pci.o
 obj-$(CONFIG_RT61PCI)			+= rt61pci.o
 obj-$(CONFIG_RT2500USB)			+= rt2500usb.o
 obj-$(CONFIG_RT73USB)			+= rt73usb.o
+obj-$(CONFIG_RT2800USB)			+= rt2800usb.o

drivers/net/wireless/rt2x00/rt2x00.h

@@ -147,6 +147,7 @@ struct rt2x00_chip {
 #define RT2561		0x0302
 #define RT2661		0x0401
 #define RT2571		0x1300
+#define RT2870		0x1600
 
 	u16 rf;
 	u32 rev;