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/P2020RDB-PC_36BIT_defconfig b/configs/P2020RDB-PC_36BIT_defconfig
index 15be73d..4de5745 100644
--- a/configs/P2020RDB-PC_36BIT_defconfig
+++ b/configs/P2020RDB-PC_36BIT_defconfig
@@ -15,6 +15,7 @@
 CONFIG_CMD_USB=y
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
+CONFIG_CMD_DATE=y
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_FAT=y
 CONFIG_MTD_NOR_FLASH=y