llvmpipe: Actually flush in lp_resource_copy()

The cpu_access is redundant in a software rasterizer.
diff --git a/src/gallium/drivers/llvmpipe/lp_surface.c b/src/gallium/drivers/llvmpipe/lp_surface.c
index 76b3fce..e8f4d19 100644
--- a/src/gallium/drivers/llvmpipe/lp_surface.c
+++ b/src/gallium/drivers/llvmpipe/lp_surface.c
@@ -67,14 +67,14 @@
                            dst, subdst.face, subdst.level,
                            0, /* flush_flags */
                            FALSE, /* read_only */
-                           FALSE, /* cpu_access */
+                           TRUE, /* cpu_access */
                            FALSE); /* do_not_block */
 
    llvmpipe_flush_resource(pipe,
                            src, subsrc.face, subsrc.level,
                            0, /* flush_flags */
                            TRUE, /* read_only */
-                           FALSE, /* cpu_access */
+                           TRUE, /* cpu_access */
                            FALSE); /* do_not_block */
 
    /*