ARC: reset: introduce HSDKv1 reset driver

The HSDK v1 periphery IPs can be reset by accessing some registers
from the CGU block.

The list of available reset lines is documented in the DT bindings.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>