meta-nios2: Add linux-altera-nios2, official Altera kernel from rocketboards

Signed-off-by: Walter Goossens <waltergoossens@home.nl>
meta-nios2: Add support for Nios2 GHRD based on the 3c120 kit

Signed-off-by: Walter Goossens <waltergoossens@home.nl>