usb: xhci: merge xhci_queue_bulk_tx and queue_bulk_sg_tx functions

In drivers/usb/host/xhci-ring.c there are two functions
(xhci_queue_bulk_tx and queue_bulk_sg_tx) that are very similar,
so a lot of code duplication.
This patch merges these functions into to one xhci_queue_bulk_tx.
Also counting the needed TRBs is merged and refactored.

Signed-off-by: Alexandr Ivanov <alexandr.sky@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci.h

@@ -1338,6 +1338,9 @@ union xhci_trb {
 /* TRB buffer pointers can't cross 64KB boundaries */
 #define TRB_MAX_BUFF_SHIFT		16
 #define TRB_MAX_BUFF_SIZE	(1 << TRB_MAX_BUFF_SHIFT)
+/* How much data is left before the 64KB boundary? */
+#define TRB_BUFF_LEN_UP_TO_BOUNDARY(addr)	(TRB_MAX_BUFF_SIZE - \
+					(addr & (TRB_MAX_BUFF_SIZE - 1)))
 
 struct xhci_segment {
 	union xhci_trb		*trbs;