IB/{core, umad, cm}: Rename ib_init_ah_from_wc to ib_init_ah_attr_from_wc

Currently ib_init_ah_from_wc initializes address handle attributes and
not the address handle object itself.
To avoid confusion between ah_attr vs ah, ib_init_ah_from_wc is
renamed to ib_init_ah_attr_from_wc to reflect that its initialzes
ah_attr.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>