Merge branch 'ptp-attribute-cleanup'

Dmitry Torokhov says:

====================
PTP attribute handling cleanup

PTP core was creating some attributes, such as "period" and "fifo", and the
entire "pins" attribute group, after creating class deevice, which creates
a race for userspace: uevent may arrive before all attributes are created.

This series of patches switches PTP to use is_visible() to control
visibility of attributes in a group, and device_create_with_groups() to
ensure that attributes are created before we notify userspace of a new
device.

v2:
- added Richard's acked-by to patch #1
- removed use of kmalloc_array in favor of kcalloc in patch #2 at
  Richard's request
- added a cover letter

v1:
- initial patch set
====================

Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>