[PATCH] Document EFI zero-page usage

From: "Randy.Dunlap" <rddunlap@osdl.org>

Add x86 EFI zero-page usage to i386 docs.

Documentation/i386/zero-page.txt

@@ -28,8 +28,13 @@ Offset	Type		Description
 
  0xa0	16 bytes	System description table truncated to 16 bytes.
 			( struct sys_desc_table_struct )
- 0xb0 - 0x1df		Free. Add more parameters here if you really need them.
+ 0xb0 - 0x1c3		Free. Add more parameters here if you really need them.
 
+0x1c4	unsigned long	EFI system table pointer
+0x1c8	unsigned long	EFI memory descriptor size
+0x1cc	unsigned long	EFI memory descriptor version
+0x1d0	unsigned long	EFI memory descriptor map pointer
+0x1d4	unsigned long	EFI memory descriptor map size
 0x1e0	unsigned long	ALT_MEM_K, alternative mem check, in Kb
 0x1e8	char		number of entries in E820MAP (below)
 0x1e9	unsigned char	number of entries in EDDBUF (below)