Revert "usb: dwc2: host: Setting qtd to NULL after freeing it"

This reverts commit b0d65902.

The reverted commit does nothing but adding two unnecessary lines
of code.  It sets a local variable to NULL in two functions, but
that variable is not used anywhere in the rest of those functions.
This is just confusing, so let's remove it.

Cc: Vardan Mikayelyan <mvardan@synopsys.com>
Cc: John Youn <johnyoun@synopsys.com>
Cc: Douglas Anderson <dianders@chromiun.org>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: NMinas Harutyunyan <hminas@synopsys.com>
Reviewed-by: NDouglas Anderson <dianders@chromium.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/hcd.c

@@ -4685,7 +4685,6 @@ static int _dwc2_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 	urb->hcpriv = NULL;
 	kfree(qtd);
-	qtd = NULL;
 fail1:
 	if (qh_allocated) {
 		struct dwc2_qtd *qtd2, *qtd2_tmp;

drivers/usb/dwc2/hcd.h

@@ -582,7 +582,6 @@ static inline void dwc2_hcd_qtd_unlink_and_free(struct dwc2_hsotg *hsotg,
 {
 	list_del(&qtd->qtd_list_entry);
 	kfree(qtd);
-	qtd = NULL;
 }
 
 /* Descriptor DMA support functions */