Instead of doing it in multiple spots lets centralize the code
to handle pci resources. This also cleans up the error
handling a bit and will make it a lot easier to add additional
svga versions to the driver.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Link: https://patchwork.freedesktop.org/patch/414040/?series=85516&rev=2