- Converted Linux drivers to initialize DRM instances based on PCI IDs, not

- Converted Linux drivers to initialize DRM instances based on PCI IDs, not
    just a single instance. Moved the PCI ID lists from <card>_drv.c in BSD
    to <card>.h. The PCI ID lists include a driver private field, which may
    be used by drivers for chip family or other information. Based on work
    by jonsmirl.
- Make tdfx_drv.c and tdfx.h match other drivers.
- Fixed up linking of sis shared files.
Tested with Radeon and SiS on Linux and FreeBSD, including a Linux setup
    with
2 SiS cards in a machine, but only one head being used (with DRI)