RDMA/umem: Avoid partial declaration of non-static function

RDMA/umem: Avoid partial declaration of non-static function

The RDMA/umem uses generic RB-trees macros to generate various ib_umem
access functions. The generation is performed with INTERVAL_TREE_DEFINE
macro, which allows one of two modes: declare all functions as static or
declare none of the function to be static.

The second mode of operation produces the following sparse errors:
 drivers/infiniband/core/umem_rbtree.c:69:1:
	warning: symbol 'rbt_ib_umem_iter_first' was not declared.
	Should it be static?
 drivers/infiniband/core/umem_rbtree.c:69:1:
	warning: symbol 'rbt_ib_umem_iter_next' was not declared.
	Should it be static?

Code relocation together with declaration of such functions to be
"static" solves the issue.

Because there is no need to have separate file for two functions,
let's consolidate umem_rtree.c and umem_odp.c into one file.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>