x86/retpoline: Add NOENDBR annotation to the SRSO dummy return thunk

stable inclusion
from stable-v5.10.215
commit 0bdc64e9e7167da915786e327af10b55fdb51c8f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAJJ2D

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0bdc64e9e7167da915786e327af10b55fdb51c8f



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commit b377c66ae3509ccea596512d6afb4777711c4870 upstream.

srso_alias_untrain_ret() is special code, even if it is a dummy
which is called in the !SRSO case, so annotate it like its real
counterpart, to address the following objtool splat:

  vmlinux.o: warning: objtool: .export_symbol+0x2b290: data relocation to !ENDBR: srso_alias_untrain_ret+0x0

Fixes: 4535e1a4174c ("x86/bugs: Fix the SRSO mitigation on Zen3/4")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240405144637.17908-1-bp@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng1 <sanglipeng1@jd.com>