arm: kirkwood: Add CONFIG_SUPPORT_PASSING_ATAGS

Add CONFIG_SUPPORT_PASSING_ATAGS and friends to support legacy
image method of booting. Debian and OpenWrt installer use uImage
with appended DTB for these Kirkwood boards.

Signed-off-by: Tony Dinh <mibodhi@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/configs/dreamplug_defconfig b/configs/dreamplug_defconfig
index 24090c8..650b146 100644
--- a/configs/dreamplug_defconfig
+++ b/configs/dreamplug_defconfig
@@ -3,6 +3,9 @@
 CONFIG_SYS_DCACHE_OFF=y
 CONFIG_ARCH_CPU_INIT=y
 CONFIG_ARCH_KIRKWOOD=y
+CONFIG_SUPPORT_PASSING_ATAGS=y
+CONFIG_CMDLINE_TAG=y
+CONFIG_INITRD_TAG=y
 CONFIG_SYS_KWD_CONFIG="board/Marvell/dreamplug/kwbimage.cfg"
 CONFIG_SYS_TEXT_BASE=0x600000
 CONFIG_NR_DRAM_BANKS=2