The uart3 setting in GPIO_MODE register is before the uart2 setting. Also
don't mix uart2 and uart3 function/groups.

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@46643 3c298f89-4303-0410-b956-a3cf2f4a3e73