RDMA/cma: Move rdma_cm_state to cma_priv.h

rdma_cm_state enum is internal to rdma_cm kernel module.
It is not required to expose state enums to ULP modules.
So lets keep its scope limited to rdma_cm module in cma_priv.h file.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>