Add fwu_plat_get_alt_num() and fwu_plat_get_bootidx() platform callbacks required for FWU multi-bank update on Versal and Versal Gen 2. The boot index is read from the PMC Global PGGS4 register which is populated by PLM with a magic number and boot partition index. Uses firmware IOCTL when CONFIG_ZYNQMP_FIRMWARE is enabled, otherwise falls back to direct MMIO read. Signed-off-by: Padmarao Begari <padmarao.begari@amd.com> Signed-off-by: Michal Simek <michal.simek@amd.com> Link: https://lore.kernel.org/r/20260514102601.1759779-6-padmarao.begari@amd.com