svga: rebind using render target surfaces in hw draw state

svga: rebind using render target surfaces in hw draw state

Currently when we rebind framebuffer resources at the beginning of
the command buffer, we use the color buffer surfaces saved in the context
hw clear state. But the surfaces could be different from the actual
emitted render target surfaces if any of the color buffer surfaces
is also used for shader resource, in that case, we create
a backed surface for the collided render target surface. So to rebind
the framebuffer resources correctly, use the render target surfaces saved
in the context hw draw state.

Tested with Heaven, Lightsmark2008, MTT piglit, glretrace, conform.

Reviewed-by: Brian Paul <brianp@vmware.com>