ARC: HSDK-4xD: use separate config file

HSDK-4xD has quite different environment so let's split
HSDK and HSDK-4xD configs file.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>