x86: fix two modpost warnings in mm/init_64.c

early_io{re,un}map() are __init and hence can't be called from __meminit
functions.

Signed-off-by: Jan Beulich <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/mm/init_64.c

···
 static unsigned long __meminitdata table_end;
 static unsigned long __meminitdata table_top;
 
-static __meminit void *alloc_low_page(unsigned long *phys)
+static __ref void *alloc_low_page(unsigned long *phys)
 {
 	unsigned long pfn = table_end++;
 	void *adr;
···
 	return adr;
 }
 
-static __meminit void unmap_low_page(void *adr)
+static __ref void unmap_low_page(void *adr)
 {
 	if (after_bootmem)
 		return;