ARC: [plat-axs103] refactor the quad core DT quirk code

Refactor the quad core DT quirk code:
get rid of waste division and multiplication by 1000000 constant.

Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>