vt6655/trivial: replace numeric with standard PM state macros

Use standard PM state macros PCI_Dx instead of numeric 0/1/2..

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Cc: Forest Bond <forest@alittletooquiet.net>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: Devendra Naga <devendra.aaru@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>