RDMA/hns: Add debugfs to hns RoCE

Add debugfs to hns RoCE. This patch only adds an empty directory
"hns_roce" to debugs root directory.

Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://lore.kernel.org/r/20231114123449.1106162-3-huangjunxian6@hisilicon.com


Signed-off-by: Leon Romanovsky <leon@kernel.org>