x86_64 linker.

Based on I8dc3e2cb596f75dc58ae82e4dc58f8c177dd3323 by
Pavel Chupin <pavel.v.chupin@intel.com>.

Change-Id: Icd582d277cbe273477b450f2848343d72c86ec9f
diff --git a/linker/linker_phdr.h b/linker/linker_phdr.h
index 28d8b39..f774b5d 100644
--- a/linker/linker_phdr.h
+++ b/linker/linker_phdr.h
@@ -46,7 +46,7 @@
 
   size_t phdr_count() { return phdr_num_; }
   Elf_Addr load_start() { return reinterpret_cast<Elf_Addr>(load_start_); }
-  Elf_Addr load_size() { return load_size_; }
+  size_t load_size() { return load_size_; }
   Elf_Addr load_bias() { return load_bias_; }
   const Elf_Phdr* loaded_phdr() { return loaded_phdr_; }
 
@@ -72,7 +72,7 @@
   // First page of reserved address space.
   void* load_start_;
   // Size in bytes of reserved address space.
-  Elf_Addr load_size_;
+  size_t load_size_;
   // Load bias.
   Elf_Addr load_bias_;