Enabling Atomic operations for Gen P5 devices if the underlying platform
supports global atomic ops.

Link: https://lore.kernel.org/r/20210603131534.982257-2-devesh.sharma@broadcom.comSigned-off-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>