net/mlx5: Fix PPLM register mapping

stable inclusion
from stable-5.10.30
commit 1312f11eb33de7014b36551dc415be22553be66c
bugzilla: 51791

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

[ Upstream commit ce28f0fd ]

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

Fixes: a58837f5 ("net/mlx5e: Expose FEC feilds and related capability bit")
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>