ralink i2c driver is not working on MT7621 platform. Porting a new drivers from MTK's source code. Signed-off-by: daixj <fl.service@t-firefly.com> git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44690 3c298f89-4303-0410-b956-a3cf2f4a3e73