You can find these files in the BSP Layer at:
meta-<bsp_name>/recipes-graphics/*
This optional directory contains recipes for the BSP if it has
special requirements for graphics support.
All files that are needed for the BSP to support a display are kept here.
For example, the Crown Bay BSP's xorg.conf
file
detects the graphics support needed (i.e. the Intel® Embedded Media
Graphics Driver (EMGD) or the Video Electronics Standards Association
(VESA) graphics):
meta-crownbay/recipes-graphics/xorg-xserver/xserver-xf86-config_0.1.bbappend meta-crownbay/recipes-graphics/xorg-xserver/xserver-xf86-config/crownbay/xorg.conf