Fix Suspend-to-RAM so that VSP1 driver continues to work after resuming.

In detail,
  - Fix the judgment of ref count in resuming.
  - Add stopping VSP1 during suspend.

[Refactor the suspend and resume code to lower suspend delay]
Signed-off-by: Sei Fumizono <sei.fumizono.jw@hitachi-solutions.com>
Signed-off-by: Yoshifumi Hosoya <yoshifumi.hosoya.wj@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>