mvebu: turris_omnia: Add CONFIG_CMD_BTRFS to defconfig

Signed-off-by: Marek Behun <marek.behun@nic.cz>
diff --git a/configs/turris_omnia_defconfig b/configs/turris_omnia_defconfig
index 870cfd51..b3f542d 100644
--- a/configs/turris_omnia_defconfig
+++ b/configs/turris_omnia_defconfig
@@ -26,6 +26,7 @@
 CONFIG_CMD_TFTPPUT=y
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_TIME=y
+CONFIG_CMD_BTRFS=y
 # CONFIG_SPL_PARTITION_UUIDS is not set
 CONFIG_ENV_IS_IN_SPI_FLASH=y
 CONFIG_SPL_OF_TRANSLATE=y