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/media/dvb/dvb-usb/usb-urb.c b/drivers/media/dvb/dvb-usb/usb-urb.c
index f9702e3..86d6893 100644
--- a/drivers/media/dvb/dvb-usb/usb-urb.c
+++ b/drivers/media/dvb/dvb-usb/usb-urb.c
@@ -96,8 +96,9 @@
 		while (stream->buf_num) {
 			stream->buf_num--;
 			deb_mem("freeing buffer %d\n",stream->buf_num);
-			usb_buffer_free(stream->udev, stream->buf_size,
-					stream->buf_list[stream->buf_num], stream->dma_addr[stream->buf_num]);
+			usb_free_coherent(stream->udev, stream->buf_size,
+					  stream->buf_list[stream->buf_num],
+					  stream->dma_addr[stream->buf_num]);
 		}
 	}
 
@@ -116,7 +117,7 @@
 	for (stream->buf_num = 0; stream->buf_num < num; stream->buf_num++) {
 		deb_mem("allocating buffer %d\n",stream->buf_num);
 		if (( stream->buf_list[stream->buf_num] =
-					usb_buffer_alloc(stream->udev, size, GFP_ATOMIC,
+					usb_alloc_coherent(stream->udev, size, GFP_ATOMIC,
 					&stream->dma_addr[stream->buf_num]) ) == NULL) {
 			deb_mem("not enough memory for urb-buffer allocation.\n");
 			usb_free_stream_buffers(stream);