PM / QoS: Remove device PM QoS sysfs attributes at the right place

Device PM QoS sysfs attributes, if present during device removal,
are removed from within device_pm_remove(), which is too late,
since dpm_sysfs_remove() has already removed the whole attribute
group they belonged to.  However, moving the removal of those
attributes to dpm_sysfs_remove() alone is not sufficient, because
in theory they still can be re-added right after being removed by it
(the device's driver is still bound to it at that point).

For this reason, move the entire desctruction of device PM QoS
constraints to dpm_sysfs_remove() and make it prevent any new
constraints from being added after it has run.  Also, move the
initialization of the power.qos field in struct device to
device_pm_init_common() and drop the no longer needed
dev_pm_qos_constraints_init().

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-fixes-next' into linux-next

* pm-fixes-next:
  PM / QoS: Remove device PM QoS sysfs attributes at the right place
  PM / QoS: Fix concurrency issues and memory leaks in device PM QoS
  cpufreq: highbank: do not initialize array with a loop
  PM / OPP: improve introductory documentation
  cpufreq: Fix a typo in comment
  mailbox, pl320-ipc: remove __init from probe function