dri2: refine dri2_probe_driver_name (v2)

V2:
1. update comment
2. check bustype if PCI
3. configure add libdrm version check for drmGetDevice

Get PCI information from info->fd with drmGetDevice instead of
assuming the info->fd is the first entity of scrn which is not
true for multi entities scrn.

Signed-off-by: Qiang Yu <Qiang.Yu@amd.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>