x86/efi: Fix off-by-one bug in EFI Boot Services reservation

commit a7f84f03 upstream.

Current code check boot service region with kernel text region by:
start+size >= __pa_symbol(_text)
The end of the above region should be start + size - 1 instead.

I see this problem in ovmf + Fedora 19 grub boot:
text start: 1000000 md start: 800000 md size: 800000
Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
[bwh: Backported to 3.2: s/__pa_symbol/virt_to_phys/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/x86/platform/efi/efi.c

@@ -424,7 +424,7 @@ void __init efi_reserve_boot_services(void)
 		 * - Not within any part of the kernel
 		 * - Not the bios reserved area
 		*/
-		if ((start+size >= virt_to_phys(_text)
+		if ((start + size > virt_to_phys(_text)
 				&& start <= virt_to_phys(_end)) ||
 			!e820_all_mapped(start, start+size, E820_RAM) ||
 			memblock_x86_check_reserved_size(&start, &size,