When kobject_init_and_add() returns an error in the function
qib_create_port_files(), the function kobject_put() is not called for the
corresponding kobject, which potentially leads to memory leak.

This patch fixes the issue by calling kobject_put() even if
kobject_init_and_add() fails. In addition, the ppd->diagc_kobj is released
along with other kobjects when the sysfs is unregistered.

Fixes: f931551b ("IB/qib: Add new qib driver for QLogic PCIe InfiniBand adapters")
Link: https://lore.kernel.org/r/20200512031328.189865.48627.stgit@awfm-01.aw.intel.com
Cc: <stable@vger.kernel.org>
Suggested-by: Lin Yi <teroincn@gmail.com>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>