x86/boot: Drop RIP_REL_REF() uses from SME startup code

x86/boot: Drop RIP_REL_REF() uses from SME startup code

RIP_REL_REF() has no effect on code residing in arch/x86/boot/startup,
as it is built with -fPIC. So remove any occurrences from the SME
startup code.

Note the SME is the only caller of cc_set_mask() that requires this, so
drop it from there as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Dionna Amalie Glaze <dionnaglaze@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kevin Loughlin <kevinloughlin@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-efi@vger.kernel.org
Link: https://lore.kernel.org/r/20250410134117.3713574-19-ardb+git@google.com