gpu: drm: radeon: Set DPM_FLAG_NEVER_SKIP when enabling PM-runtime

On HP ProBook 4540s, if PM-runtime is enabled in the radeon driver
and the direct-complete optimization is used for the radeon device
during system-wide suspend, the system doesn't resume.

Preventing direct-complete from being used with the radeon device by
setting the DPM_FLAG_NEVER_SKIP driver flag for it makes the problem
go away, which indicates that direct-complete is not safe for the
radeon driver in general and should not be used with it (at least
for now).

This fixes a regression introduced by commit c62ec461
("PM / core: Fix direct_complete handling for devices with no
callbacks") which allowed direct-complete to be applied to
devices without PM callbacks (again) which in turn unlocked
direct-complete for radeon on HP ProBook 4540s.

Fixes: c62ec461 ("PM / core: Fix direct_complete handling for devices with no callbacks")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201519


Reported-by: Ярослав Семченко <ukrkyi@gmail.com>
Tested-by: Ярослав Семченко <ukrkyi@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org