net/mlx4: remove control path locks

net/mlx4: remove control path locks

Concurrent use of various control path functions (e.g. configuring a queue
and destroying it simultaneously) may lead to undefined behavior.

PMD are not supposed to protect themselves from misbehaving applications,
and mlx4 is one of the few with internal locks on most control path
operations. This adds unnecessary complexity.

Leave this role to wrapper functions in ethdev.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>