x86: edison: Enable DFU timeout

The stock U-Boot on Intel Edison has timeout parameter for DFU command.
Enable it here to be compatible with the original U-Boot configuration.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
diff --git a/configs/edison_defconfig b/configs/edison_defconfig
index cccf1cc..14b2eec 100644
--- a/configs/edison_defconfig
+++ b/configs/edison_defconfig
@@ -33,6 +33,7 @@
 CONFIG_ENV_OFFSET_REDUND=0x600000
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_CPU=y
+CONFIG_DFU_TIMEOUT=y
 CONFIG_DFU_MMC=y
 CONFIG_DFU_RAM=y
 CONFIG_SUPPORT_EMMC_BOOT=y