IB/mlx5: Remove superfluous include of io-mapping.h

IB/mlx5: Remove superfluous include of io-mapping.h

This file does not use any structs or functions defined by io-mapping.h
(nor does it directly use iomap, ioremap, iounamp or friends). Remove it
to simplify verification of changes to io-mapping.h

The include existed since its inception in

commit e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c
Author: Eli Cohen <[email protected]>
Date:   Sun Jul 7 17:25:49 2013 +0300

    mlx5: Add driver for Mellanox Connect-IB adapters

which looks like a copy across from the Mellanox ethernet driver.

Signed-off-by: Chris Wilson <[email protected]>
Cc: Eli Cohen <[email protected]>
Cc: Jack Morgenstein <[email protected]>
Cc: Or Gerlitz <[email protected]>
Cc: Matan Barak <[email protected]>
Cc: Leon Romanovsky <[email protected]>
Cc: Doug Ledford <[email protected]>
Cc: Sean Hefty <[email protected]>
Cc: Hal Rosenstock <[email protected]>
Cc: [email protected]
Reviewed-by: Leon Romanovsky <[email protected]>
Reviewed-by: Laurence Oberman <[email protected]>
Tested-by: Laurence Oberman <[email protected]>
Signed-off-by: Doug Ledford <[email protected]>