RDMA/hfi1: Use attributes for the port sysfs

hfi1 should not be creating a mess of kobjects to attach to the port
kobject - this is all attributes. The proper API is to create an
attribute_group list and create it against the port's kobject.

Link: https://lore.kernel.org/r/cbe0ccb6175dd22274359b6ad803a37435a70e91.1623427137.git.leonro@nvidia.com


Tested-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>