driver core: firmware_class:fix memory leak of page pointers array

The page pointers array is allocated in fw_realloc_buffer() called by
firmware_data_write(), and should be freed in release function of firmware
device.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/firmware_class.c

@@ -180,7 +180,6 @@ static ssize_t firmware_loading_store(struct device *dev,
 				goto err;
 			}
 			/* Pages will be freed by vfree() */
-			fw_priv->pages = NULL;
 			fw_priv->page_array_size = 0;
 			fw_priv->nr_pages = 0;
 			complete(&fw_priv->completion);