hw/rdma: Remove deprecated pvrdma device and rdmacm-mux helper

hw/rdma: Remove deprecated pvrdma device and rdmacm-mux helper

The whole RDMA subsystem was deprecated in commit e9a54265f5
("hw/rdma: Deprecate the pvrdma device and the rdma subsystem")
released in v8.2.

Remove:
 - PVRDMA device
 - generated vmw_pvrdma/ directory from linux-headers
 - rdmacm-mux tool from contrib/

Cc: Yuval Shaia <yuval.shaia.ml@gmail.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20240328130255.52257-2-philmd@linaro.org>