mm: don't export arch_add_memory

Only x86_64 and sh export this symbol, and it is not used by any
modular code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

arch/sh/mm/init.c

@@ -498,7 +498,6 @@ int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock)
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(arch_add_memory);
 
 #ifdef CONFIG_NUMA
 int memory_add_physaddr_to_nid(u64 addr)

arch/x86/mm/init_64.c

@@ -796,7 +796,6 @@ int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock)
 
 	return add_pages(nid, start_pfn, nr_pages, want_memblock);
 }
-EXPORT_SYMBOL_GPL(arch_add_memory);
 
 #define PAGE_INUSE 0xFD