RDMA/mlx5: Check enabled UCAPs when creating ucontext

Verify that the enabled UCAPs are supported by the device before
creating the ucontext.
If supported, create the ucontext with the associated capabilities.

Store the privileged ucontext UID on creation and remove it when
destroying the privileged ucontext. This allows the command interface
to recognize privileged commands through its UID.

Signed-off-by: Chiara Meiohas <cmeiohas@nvidia.com>
Link: https://patch.msgid.link/8b180583a207cb30deb7a2967934079749cdcc44.1741261611.git.leon@kernel.org


Reviewed-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>