USB: rename usb_buffer_alloc() and usb_buffer_free() users

For more clearance what the functions actually do,

  usb_buffer_alloc() is renamed to usb_alloc_coherent()
  usb_buffer_free()  is renamed to usb_free_coherent()

They should only be used in code which really needs DMA coherency.

All call sites have been changed accordingly, except for staging
drivers.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Pedro Ribeiro <pedrib@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index 99330bb..ea41a85 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -1291,8 +1291,8 @@
 static void usbtouch_free_buffers(struct usb_device *udev,
 				  struct usbtouch_usb *usbtouch)
 {
-	usb_buffer_free(udev, usbtouch->type->rept_size,
-	                usbtouch->data, usbtouch->data_dma);
+	usb_free_coherent(udev, usbtouch->type->rept_size,
+			  usbtouch->data, usbtouch->data_dma);
 	kfree(usbtouch->buffer);
 }
 
@@ -1336,8 +1336,8 @@
 	if (!type->process_pkt)
 		type->process_pkt = usbtouch_process_pkt;
 
-	usbtouch->data = usb_buffer_alloc(udev, type->rept_size,
-	                                  GFP_KERNEL, &usbtouch->data_dma);
+	usbtouch->data = usb_alloc_coherent(udev, type->rept_size,
+					    GFP_KERNEL, &usbtouch->data_dma);
 	if (!usbtouch->data)
 		goto out_free;