JFS: define aio_read and aio_write file_operations.

This simply uses generic_file_aio_read and generic_file_aio_write

fs/jfs/file.c

@@ -102,6 +102,8 @@ struct file_operations jfs_file_operations = {
 	.llseek		= generic_file_llseek,
 	.write		= generic_file_write,
 	.read		= generic_file_read,
+	.aio_read	= generic_file_aio_read,
+	.aio_write	= generic_file_aio_write,
 	.mmap		= generic_file_mmap,
 	.readv		= generic_file_readv,
 	.writev		= generic_file_writev,