net/mlx5: Fix PBMC register mapping

stable inclusion
from stable-5.10.30
commit 03ad6a2521a05eb58367d79ed4fb91a4aefd23dc
bugzilla: 51791

--------------------------------

[ Upstream commit 534b1204 ]

Add reserved mapping to cover all the register in order to avoid setting
arbitrary values to newer FW which implements the reserved fields.

Fixes: 50b4a3c2 ("net/mlx5: PPTB and PBMC register firmware command support")
Signed-off-by: Aya Levin <ayal@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: Chen Jun <chenjun102@huawei.com>
Acked-by:   Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>