RDMA/core: Annotate timeout as unsigned long

The ucma users supply timeout in u32 format, it means that any number
with most significant bit set will be converted to negative value
by various rdma_*, cma_* and sa_query functions, which treat timeout
as int.

In the lowest level, the timeout is converted back to be unsigned long.
Remove this ambiguous conversion by updating all function signatures to
receive unsigned long.

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