svga: use the debug callback to report issues to the state tracker

svga: use the debug callback to report issues to the state tracker

Use the new debug callback hook to report conformance, performance
and fallbacks to the state tracker.  The state tracker, in turn can
report this issues to the user via the GL_ARB_debug_output extension.

More issues can be reported in the future; this is just a start.

v2: remove conditionals around pipe_debug_message() calls since the
check is now done in the macro itself.
v3: remove unneeded dummy %s substitutions

Acked-by: Ilia Mirkin <imirkin@alum.mit.edu>,
Reviewed-by: José Fonseca <jfonseca@vmware.com>