x86: convert pgalloc_64.h from macros to inlines

Convert asm-x86/pgalloc_64.h from macros into functions (#include hell
prevents __*_free_tlb from being inline, but they're probably a bit
big to inline anyway).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>