ARM64: zynqmp: Enable CMD_NAND via Kconfig

Simplify board file by enabling CMD_NAND via Kconfig.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig b/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
index 77e6180..2edd180 100644
--- a/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
+++ b/configs/xilinx_zynqmp_zc1751_xm016_dc2_defconfig
@@ -13,6 +13,7 @@
 # CONFIG_CMD_IMLS is not set
 CONFIG_CMD_MEMTEST=y
 # CONFIG_CMD_FLASH is not set
+CONFIG_CMD_NAND=y
 CONFIG_CMD_I2C=y
 CONFIG_CMD_USB=y
 CONFIG_CMD_DFU=y