drm/i915: fixup forcewake spinlock fallout in drpc debugfs function
My forcewake spinlock patches have a functional conflict with Ben
Widawsky's gen6 drpc support for debugfs. Result was a benign warning
about trying to read an non-atomic variabla with atomic_read.
Note that the entire check is racy anyway and purely informational.
Also update it to reflect the forcewake voodoo changes, the kernel can
now also hold onto a forcewake reference for longer times.
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Keith Packard <keithp@keithp.com>