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.c

@@ -474,6 +474,8 @@ void __init efi_enter_virtual_mode(void)
 	efi.reset_system = virt_efi_reset_system;
 	efi.set_virtual_address_map = virt_efi_set_virtual_address_map;
 	runtime_code_page_mkexec();
+	early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
+	memmap.map = NULL;
 }
 
 /*