[intel] Incorporate ring producer and consumer counters in diagnostics

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[linux] Add missing #include <stddef.h>

Signed-off-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[legal] Add FILE_LICENCE for valgrind headers

Signed-off-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[legal] Add FILE_LICENCE for core/errno.c

Signed-off-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[legal] Add FILE_LICENCE for ath9k driver headers

Signed-off-by: Marin Hannache <git@mareo.fr>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>