[PATCH] x86_64: Calgary IOMMU - fix off by one error

Fixed off-by-one error in detect_calgary and calgary_init which will
cause arrays to overflow.  Also, removed impossible to hit BUG_ON.

Signed-off-by: Jon Mason <jdmason@us.ibm.com>
Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>