arm: zynq: Enable FPGA/FPGA_XILINX via Kconfig

Enabling fpga via Kconfig.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/topic_miamiplus_defconfig b/configs/topic_miamiplus_defconfig
index d8f6fcf..2c080bc 100644
--- a/configs/topic_miamiplus_defconfig
+++ b/configs/topic_miamiplus_defconfig
@@ -27,6 +27,7 @@
 CONFIG_OF_EMBED=y
 CONFIG_SPL_DM_SEQ_ALIAS=y
 CONFIG_DFU_RAM=y
+CONFIG_FPGA_XILINX=y
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_ZYNQ=y
 CONFIG_SPI_FLASH=y