uts: vgatext should use gfx_private
The gfx_private is "forgotten" interface since the illumos fork was created and does already implement most of the vgatext. The purpose of the gfx_private is to provide an mechanism to implement console accesss methods, It is time to start to work on this module so we can get basic support linear framebuffer.
The purpose of this feature is to make sure we have gfx_private implementing features used in vgatext, and so we could remove the code duplication and can have basis for future work.
Since there are some references to vgatext from drm module, this change needs to attend those bits as well.