Hi Minakovd,
Yes, it is possible to change the log_mtts_per seg. It is a parameter of mlx4_core kernel module.
you will need to set it up via modprob.conf and reload the driver.
the two parameters you can change would be:
options mlx4_core log_num_mtt=<nnn>
options mlx4_core log_mtts_per_seg=<nnn>
You can check what the default values are using modinfo mlx4_core and then change to higher values.