The subroutine rxe_do_task() is only called in rxe_task.c. This patch
makes it static and renames it do_task().

Link: https://lore.kernel.org/r/20221021200118.2163-6-rpearsonhpe@gmail.comSigned-off-by: Ian Ziemba <ian.ziemba@hpe.com>
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>