qed: potential overflow in qed_cxt_src_t2_alloc()

In the current code "ent_per_page" could be more than "conn_num" making
"conn_num" negative after the subtraction.  In the next iteration
through the loop then the negative is treated as a very high positive
meaning we don't put a limit on "ent_num".  It could lead to memory
corruption.

Fixes: dbb799c3 ('qed: Initialize hardware for new protocols')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_cxt.c

@@ -850,7 +850,7 @@ static int qed_cxt_src_t2_alloc(struct qed_hwfn *p_hwfn)
 			val = 0;
 		entries[j].next = cpu_to_be64(val);
 
-		conn_num -= ent_per_page;
+		conn_num -= ent_num;
 	}
 
 	return 0;