x86: fixes some bugs about EFI memory map handling

This patch fixes some bugs of EFI memory handing code.

- On x86_64, it is possible that EFI memory map can not be mapped via
  identity map, so efi_map_memmap is removed, just use early_ioremap.

- On i386, the EFI memory map mapping take effect cross paging_init,
  so it is not necessary to use efi_map_memmap.

- EFI memory map is unmapped in efi_enter_virtual_mode to avoid
  early_ioremap leak.

Signed-off-by: Huang Ying <ying.huang@intel.com>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/efi_64.c

@@ -103,15 +103,6 @@ void __init efi_call_phys_epilog(void)
 	local_irq_restore(efi_flags);
 }
 
-/*
- * We need to map the EFI memory map again after init_memory_mapping().
- */
-void __init efi_map_memmap(void)
-{
-	memmap.map = __va(memmap.phys_map);
-	memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);
-}
-
 void __init efi_reserve_bootmem(void)
 {
 	reserve_bootmem_generic((unsigned long)memmap.phys_map,