mlx4_core: Add module parameter for number of MTTs per segment

The current MTT allocator uses kmalloc() to allocate a buffer for its
buddy allocator, and thus is limited in the amount of MTT segments
that it can control.  As a result, the size of memory that can be
registered is limited too.  This patch uses a module parameter to
control the number of MTT entries that each segment represents,
allowing more memory to be registered with the same number of
segments.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

include/linux/mlx4/device.h

@@ -210,6 +210,7 @@ struct mlx4_caps {
 	int			num_comp_vectors;
 	int			num_mpts;
 	int			num_mtt_segs;
+	int			mtts_per_seg;
 	int			fmr_reserved_mtts;
 	int			reserved_mtts;
 	int			reserved_mrws;