ia64: scrub ia64 from poison.h

Link: https://lkml.kernel.org/r/c72e5467-06a8-4739-ae6a-7c84c96cad77@p183
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Alexey Dobriyan

include/linux/poison.h

@@ -52,12 +52,6 @@
 /********** arch/$ARCH/mm/init.c **********/
 #define POISON_FREE_INITMEM	0xcc
 
-/********** arch/ia64/hp/common/sba_iommu.c **********/
-/*
- * arch/ia64/hp/common/sba_iommu.c uses a 16-byte poison string with a
- * value of "SBAIOMMU POISON\0" for spill-over poisoning.
- */
-
 /********** fs/jbd/journal.c **********/
 #define JBD_POISON_FREE		0x5b
 #define JBD2_POISON_FREE	0x5c