habanalabs: Call put_pid() when releasing control device

The refcount of the "hl_fpriv" structure is not used for the control
device, and thus hl_hpriv_put() is not called when releasing this
device.
This results with no call to put_pid(), so add it explicitly in
hl_device_release_ctrl().

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>