Use unified macros for device structs access instead of open coding the
shifts and masks over and over again.

Link: https://lore.kernel.org/r/20200225114010.21790-2-galpress@amazon.comReviewed-by: Firas JahJah <firasj@amazon.com>
Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>