RDMA/rxe: Move crc32 init code to rxe_icrc.c

This patch collects the code from rxe_register_device() that sets up the
crc32 calculation into a subroutine rxe_icrc_init() in rxe_icrc.c.

Link: https://lore.kernel.org/r/20210707040040.15434-8-rpearsonhpe@gmail.com


Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>