drm/fb-helper: Stop using mode_config.mutex for internals

drm/fb-helper: Stop using mode_config.mutex for internals

Those are now all protected using fb_helper->lock.

v2: We still need to hold mode_config.mutex right around calling
connector->fill_modes.

v3: I forgot to hold mode_config.mutex while looking at
connector->status and the mode list. Also, we need to patch up the
i915 ->initial_config callback to grab the locks it needs to inspect
the modeset state recovered from the fw.

v4: Don't reorder the probe too much (Ville).

Cc: Ville Syrjälä <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Thierry Reding <[email protected]>
Reviewed-by: Maarten Lankhorst <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]