ARC: [plat-hsdk]: Add reset controller handle to manage USB reset

DW USB controller on HSDK hangs sometimes after SW reset, so
add reset handle to make possible to reset DW USB controller HW.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>