doc: hashdist defaults on for 64bit

kernel boot parameter `hashdist' now defaults on for all 64bit NUMA.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/kernel-parameters.txt

@@ -775,7 +775,7 @@ and is between 256 and 4096 characters. It is defined in the file
 
 	hashdist=	[KNL,NUMA] Large hashes allocated during boot
 			are distributed across NUMA nodes.  Defaults on
-			for IA-64, off otherwise.
+			for 64bit NUMA, off otherwise.
 			Format: 0 | 1 (for off | on)
 
 	hcl=		[IA-64] SGI's Hardware Graph compatibility layer