soc: arc: snps_emsk: Convert to new dt macros

Convert from DT_MMIO_SRAM_10000000_BASE_ADDRESS to
DT_REG_ADDR(DT_NODELABEL(ddr0)) and similar for
DT_MMIO_SRAM_10000000_SIZE to DT_REG_SIZE().

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>