[IA64] Need export for csum_ipv6_magic

Now we have our own highly optimized assembly code version of
this routine (Thanks Ken!) we should export it so that it can
be used.
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/ia64_ksyms.c

@@ -14,6 +14,7 @@ EXPORT_SYMBOL(strlen);
 
 #include <asm/checksum.h>
 EXPORT_SYMBOL(ip_fast_csum);		/* hand-coded assembly */
+EXPORT_SYMBOL(csum_ipv6_magic);
 
 #include <asm/semaphore.h>
 EXPORT_SYMBOL(__down);