drm: panel: Add novatek nt36672a panel driver

drm: panel: Add novatek nt36672a panel driver

Novatek NT36672a is a generic DSI IC that drives command and video mode
panels. Add the driver for it.

Right now adding support for some Poco F1 phones that have an LCD panel
from Tianma connected with this IC, with a resolution of 1080x2246 that
operates in DSI video mode.

During testing, Benni Steini <bennisteinir@gmail.com> helped us fix
the reset sequence timing (from 10ms to 20ms), to get the bootanimation
to work on Android.

With current AOSP, we need to increase it to 200ms - this seems to be a
safe high value to avoid a white screen occasionally.

Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benni Steini <bennisteinir@gmail.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200902064407.30712-3-sumit.semwal@linaro.org