drm/panel: p079zca: Support Innolux P097PFG panel

Support Innolux P097PFG 9.7" 1536x2048 TFT LCD panel, it reuse
the Innolux P079ZCA panel driver.

Changes in v2:
- None
Changes in v3:
- None
Changes in v4:
- None
Changes in v5:
- Document source of init-commands
- 4 lanes per DSI interface

Signed-off-by: Lin Huang <hl@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180702102721.3546-5-heiko@sntech.de