r300,r600,radeonsi: replace RADEON_FLUSH_* with PIPE_FLUSH_*

and handle PIPE_FLUSH_HINT_FINISH in r300.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/gallium/drivers/r300/r300_blit.c

@@ -383,7 +383,7 @@ static void r300_clear(struct pipe_context* pipe,
 
         /* Reserve CS space. */
         if (!r300->rws->cs_check_space(r300->cs, dwords)) {
-            r300_flush(&r300->context, RADEON_FLUSH_ASYNC, NULL);
+            r300_flush(&r300->context, PIPE_FLUSH_ASYNC, NULL);
         }
 
         /* Emit clear packets. */