r300,r600,svga: save the FS constant buffer for u_blitter to fix a regression
Fixes: 773a23eb - gallium/u_blitter: clear color buffers using color from a constant buffer Closes: #6548 (closed) Closes: #6539 (closed)
Fixes: 773a23eb - gallium/u_blitter: clear color buffers using color from a constant buffer Closes: #6548 (closed) Closes: #6539 (closed)