imx: ventana: display 'none' for MMC if board does not have it

print 'None' instead of just a blank line if nothing is detected:
MMC:  None

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

board/gateworks/gw_ventana/common.c

@@ -1758,6 +1758,7 @@ int board_mmc_init(struct bd_info *bis)
 		return fsl_esdhc_initialize(bis, &usdhc_cfg[0]);
 	default:
 		/* doesn't have MMC */
+		printf("None");
 		return -1;
 	}
 }