IB/ipath: Fix user memory region creation when IOMMU present

The loop which initializes the user memory region from an array of
pages was using the wrong limit for the array.  This worked OK when
dma_map_sg() returned the same number as the number of pages.  This
patch fixes the problem.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>