drm/panthor: Ignore devfreq_{suspend, resume}_device() failures

drm/panthor: Ignore devfreq_{suspend, resume}_device() failures

devfreq_{resume,suspend}_device() don't bother undoing the suspend_count
modifications if something fails, so either it assumes failures are
harmless, or it's super fragile/buggy. In either case it's not something
we can address at the driver level, so let's just assume failures are
harmless for now, like is done in panfrost.

v3:
- Add R-b

v2:
- Add R-b

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Adrian Larumbe <adrian.larumbe@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241211075419.2333731-4-boris.brezillon@collabora.com