drm/i915: Permit pinning whilst the device is 'suspended'

commit e3d8affb upstream.

As pinning (allocating and binding GTT memory) does not actually invoke
GPU commands, it is safe, and indeed is attempted, during resumption
from suspension:

  [drm:intel_init_clock_gating] *ERROR* failed to pin power context: -16
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reported-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/gpu/drm/i915/i915_gem.c

@@ -2571,9 +2571,6 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
 	bool retry_alloc = false;
 	int ret;
 
-	if (dev_priv->mm.suspended)
-		return -EBUSY;
-
 	if (obj_priv->madv != I915_MADV_WILLNEED) {
 		DRM_ERROR("Attempting to bind a purgeable object\n");
 		return -EINVAL;