ramips: add initial support for SamKnows SK-WB8

package/boot/uboot-envtools/files/ramips

target/linux/ramips/base-files/etc/board.d/01_leds

target/linux/ramips/base-files/etc/board.d/02_network

target/linux/ramips/base-files/etc/diag.sh

target/linux/ramips/base-files/etc/init.d/bootcount

target/linux/ramips/base-files/lib/ramips.sh

target/linux/ramips/base-files/lib/upgrade/platform.sh

target/linux/ramips/dts/SK-WB8.dts

target/linux/ramips/image/mt7621.mk

target/linux/ramips/mt7621/profiles/samknows.mk