x86: GEODE: MFGPT: replace 'flags' field with 'avail' bit

Drop F_AVAIL and the 'flags' field, replacing with an 'avail' bit.  This
looks more understandable to me.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>