RDMA/counter: Add an is_disabled field in struct rdma_hw_stats

Add a bitmap in rdma_hw_stat structure, with each bit indicates whether
the corresponding counter is currently disabled or not. By default
hwcounters are enabled.

Link: https://lore.kernel.org/r/20211008122439.166063-6-markzhang@nvidia.com
Signed-off-by: Aharon Landau <aharonl@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>