ARM64: zynqmp: Enable eMMC boot partitions commands

Enable some additional features of the eMMC boot partitions.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

include/configs/xilinx_zynqmp.h

@@ -92,6 +92,7 @@
 #if defined(CONFIG_ZYNQ_SDHCI)
 # define CONFIG_MMC
 # define CONFIG_GENERIC_MMC
+# define CONFIG_SUPPORT_EMMC_BOOT
 # define CONFIG_SDHCI
 # ifndef CONFIG_ZYNQ_SDHCI_MAX_FREQ
 #  define CONFIG_ZYNQ_SDHCI_MAX_FREQ	200000000