x86: GEODE: MFGPT: make mfgpt_timer_setup available outside of mfgpt_32.c

We need to be called from elsewhere, and this gets some #ifdefs out
of the .c file.

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>