x86: remove dummy long from EFI stub

Commit 2e064b1e (x86, efi: Fix issue of overlapping .reloc section for
EFI_STUB) removed a dummy reloc added by commit 291f3632 (x86, efi: EFI
boot stub support), but forgot to remove the dummy long used by that
reloc.
Reviewed-by: NJordan Justen <jordan.l.justen@intel.com>
Tested-by: NLee G Rosenbaum <lee.g.rosenbaum@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

arch/x86/boot/header.S

@@ -476,6 +476,3 @@ die:
 setup_corrupt:
 	.byte	7
 	.string	"No setup signature found...\n"
-
-	.data
-dummy:	.long	0