usb: xhci: keystone: Remove common dwc3 drv functions calls

Remove all redundant dwc3 driver function calls that
are defined by dwc3 driver

Signed-off-by: Ramneek Mehresh <ramneek.mehresh@freescale.com>
diff --git a/include/configs/ks2_evm.h b/include/configs/ks2_evm.h
index e05d56c..eb4bcaf 100644
--- a/include/configs/ks2_evm.h
+++ b/include/configs/ks2_evm.h
@@ -195,6 +195,7 @@
 
 /* USB Configuration */
 #define CONFIG_USB_XHCI
+#define CONFIG_USB_XHCI_DWC3
 #define CONFIG_USB_XHCI_KEYSTONE
 #define CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS	2
 #define CONFIG_USB_STORAGE