All the date we print is invariant for the lifetime of the driver.
And none of it would be protected by the mode_config.mutex anyway.
So drop it.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
 
 #ifdef CONFIG_DRM_I915_FBDEV
        struct drm_i915_private *dev_priv = dev->dev_private;
-       int ret = mutex_lock_interruptible(&dev->mode_config.mutex);
-       if (ret)
-               return ret;
 
        ifbdev = dev_priv->fbdev;
        fb = to_intel_framebuffer(ifbdev->helper.fb);
                   atomic_read(&fb->base.refcount.refcount));
        describe_obj(m, fb->obj);
        seq_putc(m, '\n');
-       mutex_unlock(&dev->mode_config.mutex);
 #endif
 
        mutex_lock(&dev->mode_config.fb_lock);