x86: move some func calling from setup_arch to paging_init

those function depend on paging setup pgtable, so they could access
the ram in bootmem region but just get mapped.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/asm-x86/setup.h

@@ -39,6 +39,7 @@ void reserve_crashkernel(void);
 #include <asm/bootparam.h>
 
 void reserve_standard_io_resources(void);
+extern void post_reserve_initrd(void);
 
 #ifndef _SETUP