clover: add TexExtract pass to clover [WIP]

Signed-off-by: Dmitry Cherkassov <dcherkassov@gmail.com>
clover: change image class to inherit from buffer

image2d is dynamic_cast-ed down from buffer, but is not it's
direct subclass. Make it inhernit buffer.

Signed-off-by: Dmitry Cherkassov <dcherkassov@gmail.com>
r600g: add R8G8B8SNORM to FMT_8_8_8_8 texture mapping

Signed-off-by: Dmitry Cherkassov <dcherkassov@gmail.com>
r600g: add compute resource capability

Signed-off-by: Dmitry Cherkassov <dcherkassov@gmail.com>
r600g: add PIPE_TEXTURE_2D workaround

Signed-off-by: Dmitry Cherkassov <dcherkassov@gmail.com>
r600g: add basic sampler&texture metadata parsing [WIP]

Signed-off-by: Dmitry Cherkassov <dcherkassov@gmail.com>