Revert "swiotlb: fix wrong panic"

This reverts commit 484d82b.

It caused build problems on some architectures and was already asked to
be removed from the queue.  It was my fault for incorrectly applying it.

Reported-by: Shawn Bohrer <shawn.bohrer@gmail.co
Reported-by: Stefan Bader <stefan.bader@canonical.com>
Reported-by: David Engel <david@istwok.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

lib/swiotlb.c

@@ -631,10 +631,8 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 	/*
 	 * Ensure that the address returned is DMA'ble
 	 */
-	if (!dma_capable(dev, dev_addr, size)) {
-		swiotlb_tbl_unmap_single(dev, map, size, dir);
-		dev_addr = swiotlb_virt_to_bus(dev, io_tlb_overflow_buffer);
-	}
+	if (!dma_capable(dev, dev_addr, size))
+		panic("map_single: bounce buffer is not DMA'ble");
 
 	return dev_addr;
 }