bcmstb: Migrate CONFIG_CMD_EXT[24]

The common config header for bcm7260 and bcm7445 enable
CONFIG_CMD_EXT2/EXT4 but the defconfigs do not.  This results in the
commands being disabled.  Enable them via the defconfig.

Cc: Thomas Fitzsimmons <fitzsim@fitzsim.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/bcm7260_defconfig b/configs/bcm7260_defconfig
index d467e62..4ddca7c 100644
--- a/configs/bcm7260_defconfig
+++ b/configs/bcm7260_defconfig
@@ -14,6 +14,8 @@
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="U-Boot>"
 CONFIG_CMD_MMC=y
+CONFIG_CMD_EXT2=y
+CONFIG_CMD_EXT4=y
 CONFIG_EFI_PARTITION=y
 CONFIG_OF_PRIOR_STAGE=y
 CONFIG_ENV_IS_IN_MMC=y