arm: zynq: Enable DM_GPIO when needed

There are two reasons for doing this change.
There is still !DM driver for xilinx soft gpio IP and especially it is
saving some space for memory constrained boards like cse (almost ~400B).

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/topic_miamiplus_defconfig b/configs/topic_miamiplus_defconfig
index d511a94..e2d6c93 100644
--- a/configs/topic_miamiplus_defconfig
+++ b/configs/topic_miamiplus_defconfig
@@ -30,6 +30,7 @@
 CONFIG_SPL_DM_SEQ_ALIAS=y
 CONFIG_DFU_RAM=y
 CONFIG_FPGA_XILINX=y
+CONFIG_DM_GPIO=y
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_ZYNQ=y
 CONFIG_SPI_FLASH=y