drm/panel: Add Kingdisplay KD097D04 panel driver

drm/panel: Add Kingdisplay KD097D04 panel driver

Support Kingdisplay KD097D04 9.7" 1536x2048 TFT LCD panel, it is a MIPI
dual-DSI panel.

v4-resend:
- Thierry noted missing dt-bindings for v4 but forgot that he
  already had applied them one kernel release back in
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ebc950fdff6d5f9250cd5a5a348af97f7d8508df
v4:
- address Philipp's comments
  - real range for usleep_range and
  - poweroff ordering in kingdisplay_panel_prepare
  - return value beautification in panel_probe
- update author naming for full name
v3:
- address Thierry's comments
  - error handling for init dsi writes in init
  - unconditionally remove the panel
  - don't use drm_panel_detach
  - a bit of variable signednes wiggling
- I did talk to ChromeOS people and the delays really should be as short
  as possible, so dropped the 100ms from the delay comments
v2:
- update timing + cmds from chromeos kernel
- new backlight API including switch to devm_of_find_backlight
- fix most of Sean Paul's comments
  enable/prepare tracking seems something all panels do
- document origins of the init sequence
- lanes per dsi interface to 4 (two interfaces). Matches how tegra
  and pending rockchip dual-dsi handle (dual-)dsi lanes
- spdx header instead of license boilerplate

Signed-off-by: Nickey Yang <nickey.yang@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181030091528.28211-1-heiko@sntech.de