x86, realmode: Separate real_mode reserve and setup

After we switch to use #PF handler help to set page table, init_level4_pgt
will only have entries set after init_mem_mapping().
We need to move copying init_level4_pgt to trampoline_pgd after that.

So split reserve and setup, and move the setup after init_mem_mapping()

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-11-git-send-email-yinghai@kernel.org
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/setup.c

@@ -999,12 +999,14 @@ void __init setup_arch(char **cmdline_p)
 	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
 			(max_pfn_mapped<<PAGE_SHIFT) - 1);
 
-	setup_real_mode();
+	reserve_real_mode();
 
 	trim_platform_memory_ranges();
 
 	init_mem_mapping();
 
+	setup_real_mode();
+
 	memblock.current_limit = get_max_mapped();
 	dma_contiguous_reserve(0);