nitrogen6x: config: enable USB keyboard support

Enable the use of USB keyboards on SABRE Lite and Nitrogen6x boards.

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
diff --git a/include/configs/nitrogen6x.h b/include/configs/nitrogen6x.h
index b31b922..d505191 100644
--- a/include/configs/nitrogen6x.h
+++ b/include/configs/nitrogen6x.h
@@ -122,6 +122,8 @@
 #define CONFIG_EHCI_HCD_INIT_AFTER_RESET	/* For OTG port */
 #define CONFIG_MXC_USB_PORTSC	(PORT_PTS_UTMI | PORT_PTS_PTW)
 #define CONFIG_MXC_USB_FLAGS	0
+#define CONFIG_USB_KEYBOARD
+#define CONFIG_SYS_USB_EVENT_POLL_VIA_CONTROL_EP
 
 /* Miscellaneous commands */
 #define CONFIG_CMD_BMODE