RDMA/qedr: Add kernel capability flags for dpm enabled mode

RDMA/qedr: Add kernel capability flags for dpm enabled mode

HW/FW support two types of latency enhancement features.  Until now
user-space implemented only edpm (enhanced dpm).  We add kernel capability
flags to differentiate between current FW in kernel that supports both
ldpm and edpm.  Since edpm is not yet supported for iWARP we add different
flags for iWARP + RoCE.  We also fix bad practice of defining sizes in
rdma-core and pass initialization to kernel, for forward compatibility.

The capability flags are added for backward-forward compatibility between
kernel and rdma-core for qedr.

Before this change there was a field called dpm_enabled which could hold
either 0 or 1 value, this indicated whether RoCE edpm was enabled or
not. We modified this field to be dpm_flags, and bit 1 still holds the
same meaning of RoCE edpm being enabled or not.

Link: https://lore.kernel.org/r/20191121112957.25162-1-michal.kalderon@marvell.com
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>