ndctl: release v52

This release incorporates the capabilities of the 4.6 kernel (most
prominently 'clear poison' support), and adds the below features and
fixes:

New apis:
ndctl_invalidate
ndctl_cmd_ars_cap_get_range
ndctl_bus_cmd_new_clear_error
ndctl_cmd_clear_error_get_cleared
ndctl_namespace_get_resource
ndctl_pfn_get_size
ndctl_pfn_get_resource

Api fixes:
ndctl_bus_cmd_new_ars_status - output buffer sizing fix
ndctl_bus_cmd_new_ars_status - input validation
ndctl_cmd_ars_in_progress - invalidate state after checking