RDMA: Clean destroy CQ in drivers do not return errors

Like all other destroy commands, .destroy_cq() call is not supposed
to fail. In all flows, the attempt to return earlier caused to memory
leaks.

This patch converts .destroy_cq() to do not return any errors.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Gal Pressman <galpress@amazon.com>
Acked-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mthca/mthca_provider.c

@@ -804,7 +804,7 @@ out:
 	return ret;
 }
 
-static int mthca_destroy_cq(struct ib_cq *cq, struct ib_udata *udata)
+static void mthca_destroy_cq(struct ib_cq *cq, struct ib_udata *udata)
 {
 	if (udata) {
 		struct mthca_ucontext *context =
@@ -824,8 +824,6 @@ static int mthca_destroy_cq(struct ib_cq *cq, struct ib_udata *udata)
 	}
 	mthca_free_cq(to_mdev(cq->device), to_mcq(cq));
 	kfree(cq);
-
-	return 0;
 }
 
 static inline u32 convert_access(int acc)