RDMA/mlx5: Fix validation of max_rd_atomic caps for DC

RDMA/mlx5: Fix validation of max_rd_atomic caps for DC

[ Upstream commit 6608eb194e315ac91c455ce09b488af3ccb3f6fd ]

Currently, when modifying DC, we validate max_rd_atomic user attribute
against the RC cap, validate against DC. RC and DC QP types have different
device limitations.

This can cause userspace created DC QPs to malfunction.

Fixes: 601d748eeff9 ("IB/mlx5: Add support for DC Initiator QP")
Link: https://lore.kernel.org/r/0c5aee72cea188c3bb770f4207cce7abc9b6fc74.1672231736.git.leonro@nvidia.com
Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>