sparc64: Do not define BIO_VMERGE_BOUNDARY.

The IOMMU code and the block layer can split things
up using different rules, so this can't work reliably.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/asm-sparc/io_64.h

@@ -16,7 +16,6 @@
 /* BIO layer definitions. */
 extern unsigned long kern_base, kern_size;
 #define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
-#define BIO_VMERGE_BOUNDARY	8192
 
 static inline u8 _inb(unsigned long addr)
 {