IB/mthca: Fix off-by-one in FMR handling on memfree

mthca_table_find() will return the wrong address when the table entry
being searched for is exactly at the beginning of a sglist entry
(other than the first), because it uses >= when it should use >.

Example: assume we have 2 entries in scatterlist, 4K each, offset is
4K.  The current code will return first entry + 4K when we really want
the second entry.

In particular this means mapping an FMR on a memfree HCA may end up
writing the page table into the wrong place, leading to memory
corruption and also causing the HCA to use an incorrect address
translation table.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mthca/mthca_memfree.c

@@ -232,7 +232,7 @@ void *mthca_table_find(struct mthca_icm_table *table, int obj)
 
 	list_for_each_entry(chunk, &icm->chunk_list, list) {
 		for (i = 0; i < chunk->npages; ++i) {
-			if (chunk->mem[i].length >= offset) {
+			if (chunk->mem[i].length > offset) {
 				page = chunk->mem[i].page;
 				goto out;
 			}