x86: rename two e820 related functions

rename update_memory_range to e820_update_range
rename add_memory_region to e820_add_region

to make it more clear that they are about e820 map operations.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mach-default/setup.c b/arch/x86/mach-default/setup.c
index 56b4c39..7ae692a 100644
--- a/arch/x86/mach-default/setup.c
+++ b/arch/x86/mach-default/setup.c
@@ -184,8 +184,8 @@
 		}
 
 		e820.nr_map = 0;
-		add_memory_region(0, LOWMEMSIZE(), E820_RAM);
-		add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
+		e820_add_region(0, LOWMEMSIZE(), E820_RAM);
+		e820_add_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
   	}
 	return who;
 }