misc vmwgfx fixes.

* 'drm-vmwgfx-fixes' of git://people.freedesktop.org/~syeh/repos_linux:
  drm/vmwgfx: constify pci_device_id.
  drm/vmwgfx: Fix gcc-7.1.1 warning
  drm/vmwgfx: Fix cursor hotspot issue with Wayland on Fedora
  drm/vmwgfx: Limit max desktop dimensions to 8Kx8K
  drm/vmwgfx: dma-buf: Constify ttm_place structures.
  drm/vmwgfx: fix comment mistake for vmw_cmd_dx_set_index_buffer()
  drm/vmwgfx: Use dma_pool_zalloc
  drm/vmwgfx: Fix handling of errors returned by 'vmw_cotable_alloc()'
  drm/vmwgfx: Fix NULL pointer comparison