drm/i915: don't use a temp buffer for opregion debugfs file

Hasn't been necessary since

commit 115719fceaa733d646e39cdce83cc32ddb891a49
Author: Williams, Dan J <dan.j.williams@intel.com>
Date:   Mon Oct 12 21:12:57 2015 +0000

    i915: switch from acpi_os_ioremap to memremap

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/74664a556a56d0eceb0029bbd77ffc1d771b0628.1450089383.git.jani.nikula@intel.com

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1842,25 +1842,18 @@ static int i915_opregion(struct seq_file *m, void *unused)
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_opregion *opregion = &dev_priv->opregion;
-	void *data = kmalloc(OPREGION_SIZE, GFP_KERNEL);
 	int ret;
 
-	if (data == NULL)
-		return -ENOMEM;
-
 	ret = mutex_lock_interruptible(&dev->struct_mutex);
 	if (ret)
 		goto out;
 
-	if (opregion->header) {
-		memcpy(data, opregion->header, OPREGION_SIZE);
-		seq_write(m, data, OPREGION_SIZE);
-	}
+	if (opregion->header)
+		seq_write(m, opregion->header, OPREGION_SIZE);
 
 	mutex_unlock(&dev->struct_mutex);
 
 out:
-	kfree(data);
 	return 0;
 }