83xx/fdt_support: let user specifiy FSL USB Dual-Role controller role

Linux understands "host" (default), "peripheral" and "otg" (broken).
Though, U-Boot doesn't restrict dr_mode variable to these values (think
of renames in future).

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
diff --git a/include/configs/MPC837XERDB.h b/include/configs/MPC837XERDB.h
index b2f54e1..90812e9 100644
--- a/include/configs/MPC837XERDB.h
+++ b/include/configs/MPC837XERDB.h
@@ -591,6 +591,8 @@
 #define CONFIG_ETH1ADDR		00:04:9f:ef:04:02
 #endif
 
+#define CONFIG_HAS_FSL_DR_USB
+
 #define CONFIG_IPADDR		10.0.0.2
 #define CONFIG_SERVERIP		10.0.0.1
 #define CONFIG_GATEWAYIP	10.0.0.1