imx: riotboard: Enable thermal DM support

Signed-off-by: Nikolay Dimitrov <picmaster@mail.bg>
diff --git a/configs/riotboard_defconfig b/configs/riotboard_defconfig
index c0b689b..ae0036a 100644
--- a/configs/riotboard_defconfig
+++ b/configs/riotboard_defconfig
@@ -1,3 +1,5 @@
 CONFIG_ARM=y
 CONFIG_TARGET_EMBESTMX6BOARDS=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/boundary/nitrogen6x/nitrogen6s1g.cfg,MX6S,DDR_MB=1024,ENV_IS_IN_MMC"
+CONFIG_DM=y
+CONFIG_DM_THERMAL=y