x86: Fix typo in kexec register clearing

Fixes a typo in register clearing code. Thanks to PaX Team for fixing
this originally, and James Troup for pointing it out.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20130605184718.GA8396@www.outflux.net
Cc: <stable@vger.kernel.org> v2.6.30+
Cc: PaX Team <pageexec@freemail.hu>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/relocate_kernel_64.S

@@ -160,7 +160,7 @@ identity_mapped:
 	xorq    %rbp, %rbp
 	xorq	%r8,  %r8
 	xorq	%r9,  %r9
-	xorq	%r10, %r9
+	xorq	%r10, %r10
 	xorq	%r11, %r11
 	xorq	%r12, %r12
 	xorq	%r13, %r13