Revert "x86/ftrace: Use alternative RET encoding"

stable inclusion
from stable-v5.10.144
commit 33015556a943d6cbb18c555925a54b8c0e46f521
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WL0J
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=33015556a943d6cbb18c555925a54b8c0e46f521



--------------------------------

This reverts commit 00b136bb6254e0abf6aaafe62c4da5f6c4fea4cb.

This temporarily reverts the backport of upstream commit
1f001e9d. It was not correct to copy the
ftrace stub as it would contain a relative jump to the return thunk which
would not apply to the context where it was being copied to, leading to
ftrace support to be broken.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lin Yujun <linyujun809@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>