drm/vmwgfx: Add universal plane support

Universal support is prerequisite for atomic mode set.

Explicitly create planes for the cursor and the primary FB.  With
a functional cursor plane, the DRM will no longer use the legacy
cursor_set2 and cursor_move entry points.

Signed-off-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>