net/mlx5: Fix size field in bufferx_reg struct

net/mlx5: Fix size field in bufferx_reg struct

BugLink: https://bugs.launchpad.net/bugs/1969672
[ Upstream commit ac77998b7ac3044f0509b097da9637184598980d ]

According to HW spec the field "size" should be 16 bits
in bufferx register.

Fixes: e281682bf294 ("net/mlx5_core: HW data structs/types definitions cleanup")
Signed-off-by: Mohammad Kabat <mohammadkab@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>