x86, memblock: Add memblock_x86_to_bootmem()

memblock_x86_to_bootmem() will reserve memblock.reserved.region in
bootmem after bootmem is set up.

We can use it to with all arches that support memblock later.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/include/asm/memblock.h b/arch/x86/include/asm/memblock.h
index c14219a..69cf853 100644
--- a/arch/x86/include/asm/memblock.h
+++ b/arch/x86/include/asm/memblock.h
@@ -4,5 +4,6 @@
 #define ARCH_DISCARD_MEMBLOCK
 
 u64 memblock_x86_find_in_range_size(u64 start, u64 *sizep, u64 align);
+void memblock_x86_to_bootmem(u64 start, u64 end);
 
 #endif