Convert CONFIG_CMD_FPGAD to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_FPGAD

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/hrcon_dh_defconfig b/configs/hrcon_dh_defconfig
index ce8b797..c5512e7 100644
--- a/configs/hrcon_dh_defconfig
+++ b/configs/hrcon_dh_defconfig
@@ -14,6 +14,7 @@
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_MMC=y
 CONFIG_CMD_I2C=y
+CONFIG_CMD_FPGAD=y
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_EXT2=y