As the functionality to convert the MTU from a number to enum_ib_mtu
is ubiquitous, define a dedicated function and remove the duplicated
code.
Signed-off-by: NRam Amrani <Ram.Amrani@cavium.com>
Reviewed-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>