arm64: zynqmp: Enable ISSI flash for some platforms

Enable ISSI flash for platforms. Xilinx reference boards are also used
internally with different flash part to increase coverage that's why
enable also ISSI parts for all these boards even if that board is
released only with one part.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/xilinx_zynqmp_zc1751_xm018_dc4_defconfig b/configs/xilinx_zynqmp_zc1751_xm018_dc4_defconfig
index 82dc2cb..c5dcf2e 100644
--- a/configs/xilinx_zynqmp_zc1751_xm018_dc4_defconfig
+++ b/configs/xilinx_zynqmp_zc1751_xm018_dc4_defconfig
@@ -49,6 +49,7 @@
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_BAR=y
 CONFIG_SF_DUAL_FLASH=y
+CONFIG_SPI_FLASH_ISSI=y
 CONFIG_SPI_FLASH_MACRONIX=y
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_SPI_FLASH_STMICRO=y