drm/panel-edp: Split eDP panels out of panel-simple

The panel-simple driver handles way too much. Let's start trying to
get a handle on it by splitting out the eDP panels. This patch does
this:

1. Start by copying simple-panel verbatim over to a new driver,
   simple-panel-edp.
2. Rename "panel_simple" to "panel_edp" in the new driver.
3. Keep only panels marked with `DRM_MODE_CONNECTOR_eDP` in the new
   driver. Remove those panels from the old driver.
4. Remove all recent "DP AUX bus" stuff from the old driver. The DP
   AUX bus is only possible on DP panels.
5. Remove all DSI / MIPI related functions from the new driver.
6. Remove bus_format / bus_flags from eDP driver. These things don't
   seem to make any sense for eDP panels so let's stop filling in made
   up stuff.

In the end we end up with a bunch of duplicated code for now. Future
patches will try to address _some_ of this duplicated code though some
of it will be unavoidable.

NOTE: This may not actually move all eDP panels over to the new driver
since not all panels were properly marked with
`DRM_MODE_CONNECTOR_eDP`. A future patch will attempt to move wayward
panels I could identify but even so there may be some missed.
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210914132020.v5.7.I0a2f75bb822d17ce06f5b147734764eeb0c3e3df@changeid

drivers/gpu/drm/panel/Kconfig

@@ -77,14 +77,26 @@ config DRM_PANEL_LVDS
 	  backlight handling if the panel is attached to a backlight controller.
 
 config DRM_PANEL_SIMPLE
-	tristate "support for simple panels"
+	tristate "support for simple panels (other than eDP ones)"
+	depends on OF
+	depends on BACKLIGHT_CLASS_DEVICE
+	depends on PM
+	select VIDEOMODE_HELPERS
+	help
+	  DRM panel driver for dumb non-eDP panels that need at most a regulator
+	  and a GPIO to be powered up. Optionally a backlight can be attached so
+	  that it can be automatically turned off when the panel goes into a
+	  low power state.
+
+config DRM_PANEL_EDP
+	tristate "support for simple Embedded DisplayPort panels"
 	depends on OF
 	depends on BACKLIGHT_CLASS_DEVICE
 	depends on PM
 	select VIDEOMODE_HELPERS
 	select DRM_DP_AUX_BUS
 	help
-	  DRM panel driver for dumb panels that need at most a regulator and
+	  DRM panel driver for dumb eDP panels that need at most a regulator and
 	  a GPIO to be powered up. Optionally a backlight can be attached so
 	  that it can be automatically turned off when the panel goes into a
 	  low power state.

drivers/gpu/drm/panel/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_DRM_PANEL_BOE_TV101WUM_NL6) += panel-boe-tv101wum-nl6.o
 obj-$(CONFIG_DRM_PANEL_DSI_CM) += panel-dsi-cm.o
 obj-$(CONFIG_DRM_PANEL_LVDS) += panel-lvds.o
 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
+obj-$(CONFIG_DRM_PANEL_EDP) += panel-edp.o
 obj-$(CONFIG_DRM_PANEL_ELIDA_KD35T133) += panel-elida-kd35t133.o
 obj-$(CONFIG_DRM_PANEL_FEIXIN_K101_IM2BA02) += panel-feixin-k101-im2ba02.o
 obj-$(CONFIG_DRM_PANEL_FEIYANG_FY07024DI26A30D) += panel-feiyang-fy07024di26a30d.o