cmd: add Kconfig option for 'date' command

Signed-off-by: Chris Packham <judge.packham@gmail.com>
[trini: default y if DM_RTC, re-sync]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/xpedite517x_defconfig b/configs/xpedite517x_defconfig
index 1358b79..909efb1 100644
--- a/configs/xpedite517x_defconfig
+++ b/configs/xpedite517x_defconfig
@@ -14,6 +14,7 @@
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_SNTP=y
+CONFIG_CMD_DATE=y
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_SYS_NS16550=y