nvc0: expose robust buffer access

We apparently pass all the relevant CTS tests. There are probably some
shortcomings, but they can be addressed down the line.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
diff --git a/docs/GL3.txt b/docs/GL3.txt
index ff940ff..aa58e4a 100644
--- a/docs/GL3.txt
+++ b/docs/GL3.txt
@@ -177,7 +177,7 @@
   GL_ARB_invalidate_subdata                             DONE (all drivers)
   GL_ARB_multi_draw_indirect                            DONE (i965, nvc0, r600, radeonsi, llvmpipe, softpipe, swr)
   GL_ARB_program_interface_query                        DONE (all drivers)
-  GL_ARB_robust_buffer_access_behavior                  DONE (i965, radeonsi)
+  GL_ARB_robust_buffer_access_behavior                  DONE (i965, nvc0, radeonsi)
   GL_ARB_shader_image_size                              DONE (i965, radeonsi, softpipe)
   GL_ARB_shader_storage_buffer_object                   DONE (i965, nvc0, radeonsi, softpipe)
   GL_ARB_stencil_texturing                              DONE (i965/gen8+, nv50, nvc0, r600, radeonsi, llvmpipe, softpipe, swr)