[PATCH] x86_64: cpu_pda array to macro followup correction

Fix one place where the previous change of cpu_pda from being an array
to being a macro was not properly carried out.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>