ARM: imx: Include on-SoM microSD in list of i.MX6 DHCOM boot devices

Add mmc1, which is mapped to optional on-SoM microSD socket,
to the list of distro boot command boot devices.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
diff --git a/include/configs/dh_imx6.h b/include/configs/dh_imx6.h
index 5cf7327..e9b382a 100644
--- a/include/configs/dh_imx6.h
+++ b/include/configs/dh_imx6.h
@@ -58,6 +58,7 @@
 
 #define BOOT_TARGET_DEVICES(func) \
 	func(MMC, mmc, 0) \
+	func(MMC, mmc, 1) \
 	func(MMC, mmc, 2) \
 	func(USB, usb, 1) \
 	func(SATA, sata, 0) \