arc: em7d: Add support for em starterkit 2.2 EM7D

Since em starterkit has different firmware versions(2.2 and 2.3),
but the EM7D of 2.3 has new secureshield feature, which is not supported
in Zephyr, but EM7D of 2.2 is a normal EM core, which can be supported,
so we add support for 2.2 EM7D.

Signed-off-by: Huaqi Fang <huaqi.fang@synopsys.com>