net/mlx5: Fix size field in bufferx_reg struct

stable inclusion
from stable-v5.10.106
commit 5f1340963b11bb03a5b2fc5b9f577eeeabb0d71c
bugzilla: https://gitee.com/openeuler/kernel/issues/I573US

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5f1340963b11bb03a5b2fc5b9f577eeeabb0d71c



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[ Upstream commit ac77998b ]

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

Fixes: e281682b ("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: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>