I think that's way past the point where it decides which driver to use. The problem is more likely to be that whatever the PCI vendor/device id is of your graphics card is not listed as supported by the ati or radeon drivers though it looks ok when I check my system here running 3.10.0-862.3.2.el7.x86_64 using
Interesting, doing a lspci -nn gave me a PCI ID of 1002:9807 and doing modinfo radeon | grep 1002 | grep 9807 shows as alias for it exacetly the same as you gave me. So not that sadly.
I've given up with this machine now as have gotten nowhere. Aquired an all in one machine with an Intel Celeron 847 (Asus 1612) and intel hd graphics that just work out of the box with the external HDMI TV.
Only problem with this one is that it won't actually acpi shutdown. Just hangs on halting system. Ho hum...