xilinx: Add option to select SC id instead of DUT id for SC support

Reading MAC address from on board EEPROM requires different type for System
Controller (SC).

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/90bb7cc5463568a690b979f18c8d42556986b46d.1669204122.git.michal.simek@amd.com