omap3: overo: Add DTS support for TobiDuo expansion

Signed-off-by: Arun Bharadwaj <arun@gumstix.com>
Signed-off-by: Ash Charles <ashcharles@gmail.com>
diff --git a/board/overo/overo.c b/board/overo/overo.c
index 0c2be4c..b64cfaa 100644
--- a/board/overo/overo.c
+++ b/board/overo/overo.c
@@ -287,6 +287,7 @@
 			expansion_config.revision,
 			expansion_config.fab_revision);
 		MUX_GUMSTIX();
+		setenv("expansionname", "tobiduo");
 		break;
 	case GUMSTIX_PALO35:
 		printf("Recognized Palo35 expansion board (rev %d %s)\n",