ARC: nSIM: hs5x: align sys clock with other SMP nSIM configs

Align SYS_CLOCK_HW_CYCLES_PER_SEC with other SMP nSIM
configurations and set it to 1000000.

This significantly reduce verification time on HS5x platforms.

Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>