Add ar7-2.6 port (marked as broken for now).

target/linux/ar7-2.6/Makefile

target/linux/ar7-2.6/config/default

target/linux/ar7-2.6/files/arch/mips/ar7/Makefile

target/linux/ar7-2.6/files/arch/mips/ar7/gpio.c

target/linux/ar7-2.6/files/arch/mips/ar7/irq.c

target/linux/ar7-2.6/files/arch/mips/ar7/memory.c

target/linux/ar7-2.6/files/arch/mips/ar7/platform.c

target/linux/ar7-2.6/files/arch/mips/ar7/prom.c

target/linux/ar7-2.6/files/arch/mips/ar7/setup.c

target/linux/ar7-2.6/files/arch/mips/ar7/time.c

target/linux/ar7-2.6/files/arch/mips/ar7/vlynq-pci.c

target/linux/ar7-2.6/files/arch/mips/ar7/vlynq.c

target/linux/ar7-2.6/files/drivers/char/ar7_gpio.c

target/linux/ar7-2.6/files/drivers/char/watchdog/ar7_wdt.c

target/linux/ar7-2.6/files/drivers/leds/leds-ar7.c

target/linux/ar7-2.6/files/drivers/mtd/ar7part.c

target/linux/ar7-2.6/files/drivers/net/cpmac.c

target/linux/ar7-2.6/files/include/asm-generic/gpio.h

target/linux/ar7-2.6/files/include/asm-mips/ar7/ar7.h

target/linux/ar7-2.6/files/include/asm-mips/ar7/gpio.h