ODP is working with userspace VA's in the interval tree which always fit
into an unsigned long, so we can use the common code.

This comes at a cost of a 16 byte increase in ib_umem_odp struct size due
to storing the interval tree start/last in addition to the umem
addr/length. However these values were computed and are performance
critical for the interval lookup, so this seems like a worthwhile trade
off.

Removes 2k of .text from the kernel.

Link: https://lore.kernel.org/r/20190819111710.18440-2-leon@kernel.orgSigned-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>