RDMA/hns: Fix spelling mistake "epmty" -> "empty"

There is a spelling mistake in a dev_dbg message. Fix it.

Link: https://lore.kernel.org/r/20200805141111.22804-1-colin.king@canonical.com


Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>