[PATCH 0/4] vmwgfx prime implementation

[Thomas Hellstrom]

Adds a prime implementation to the vmwgfx driver mostly for inter-process
sharing of buffers.
For now, the dma_bufs we export can't be consumed by another device and also
we don't import any dma_bufs other than the ones we've created ourselves.
This is because there are no other virtual devices that import / export
dma_bufs yet.
Basically this also means we don't have to implement the dma_buf ops