net/mlx5e: Remove duplicate mkey from SHAMPO header

SHAMPO structure holds two variations of the mkey, which is unnecessary,
a duplication that's repeated per rq.

Remove duplicate mkey information and keep only one version, the one
used in the fast path, rename field to reflect field type clearly.

Signed-off-by: Lama Kayal <lkayal@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/1753081999-326247-4-git-send-email-tariqt@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>