[PATCH] blkdev.h fixes

Patch from William Lee Irwin III <wli@holomorphy.com>

BLK_BOUNCE_HIGH and BLK_BOUNCE_ANY are compared against 64-bit quantities.
Cast these unsigned long quantities to avoid overflow.

include/linux/blkdev.h

@@ -287,8 +287,8 @@ extern unsigned long blk_max_low_pfn, blk_max_pfn;
  * BLK_BOUNCE_ANY	: don't bounce anything
  * BLK_BOUNCE_ISA	: bounce pages above ISA DMA boundary
  */
-#define BLK_BOUNCE_HIGH		(blk_max_low_pfn << PAGE_SHIFT)
-#define BLK_BOUNCE_ANY		(blk_max_pfn << PAGE_SHIFT)
+#define BLK_BOUNCE_HIGH		((u64)blk_max_low_pfn << PAGE_SHIFT)
+#define BLK_BOUNCE_ANY		((u64)blk_max_pfn << PAGE_SHIFT)
 #define BLK_BOUNCE_ISA		(ISA_DMA_THRESHOLD)
 
 extern int init_emergency_isa_pool(void);