devlink: Add dump support for device-level resources

devlink: Add dump support for device-level resources

Add dumpit handler for resource-dump command to iterate over all devlink
devices and show their resources.

  $ devlink resource show
  pci/0000:08:00.0:
    name local_max_SFs size 508 unit entry
    name external_max_SFs size 508 unit entry
  pci/0000:08:00.1:
    name local_max_SFs size 508 unit entry
    name external_max_SFs size 508 unit entry

Signed-off-by: Or Har-Toov <ohartoov@nvidia.com>
Reviewed-by: Shay Drori <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260407194107.148063-6-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>