IB/hfi1: No need to use try_module_get for debugfs

The call in debugfs.c for try_module_get() is not needed. A reference to
the module will be taken by the VFS layer as long as the owner field is
set in the file ops struct. So set this as well as remove the call.

Suggested-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>