xen: make install_p2mtop_page() static

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

arch/x86/xen/mmu.h

@@ -12,7 +12,6 @@ enum pt_level {
 
 
 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
-bool install_p2mtop_page(unsigned long pfn, unsigned long *p);
 
 void set_pte_mfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);