Use is_power_of_2() instead of hard coding it in the driver. While at it,
fix the meaningless error print.
Signed-off-by: NGal Pressman <galpress@amazon.com>
Acked-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>