cns3xxx: add linux 3.8 support and use it by default

target/linux/cns3xxx/Makefile

target/linux/cns3xxx/config-3.8

target/linux/cns3xxx/files/arch/arm/mach-cns3xxx/headsmp.S

target/linux/cns3xxx/files/arch/arm/mach-cns3xxx/platsmp.c

target/linux/cns3xxx/files/drivers/i2c/busses/i2c-cns3xxx.c

...x/cns3xxx/files/drivers/net/ethernet/cavium/cns3xxx_eth.c

target/linux/cns3xxx/files/drivers/spi/spi-cns3xxx.c

target/linux/cns3xxx/files/drivers/usb/dwc/otg_driver.c

target/linux/cns3xxx/files/drivers/usb/dwc/otg_pcd.c

...linux/cns3xxx/patches-3.8/010-move_virtual_io_space.patch

target/linux/cns3xxx/patches-3.8/015-clkdev_support.patch

target/linux/cns3xxx/patches-3.8/020-watchdog_support.patch

target/linux/cns3xxx/patches-3.8/021-cache_force_multi.patch

target/linux/cns3xxx/patches-3.8/025-smp_support.patch

target/linux/cns3xxx/patches-3.8/030-pcie_clock.patch

target/linux/cns3xxx/patches-3.8/035-add_io_spaces.patch

target/linux/cns3xxx/patches-3.8/040-fiq_support.patch

target/linux/cns3xxx/patches-3.8/045-twd_base.patch

target/linux/cns3xxx/patches-3.8/055-pcie_io.patch

target/linux/cns3xxx/patches-3.8/060-pcie_abort.patch