IB/core: Declare local functions 'static'

This patch avoids that sparse complains about missing function
declarations.

Fixes: f27a0d5 ("RDMA/umem: Use umem->owning_mm inside ODP")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/umem_odp.c

@@ -299,7 +299,7 @@ static void free_per_mm(struct rcu_head *rcu)
 	kfree(container_of(rcu, struct ib_ucontext_per_mm, rcu));
 }
 
-void put_per_mm(struct ib_umem_odp *umem_odp)
+static void put_per_mm(struct ib_umem_odp *umem_odp)
 {
 	struct ib_ucontext_per_mm *per_mm = umem_odp->per_mm;
 	struct ib_ucontext *ctx = umem_odp->umem.context;