resume_user_mode: Remove #ifdef TIF_NOTIFY_RESUME in set_notify_resume

Every architecture defines TIF_NOTIFY_RESUME so remove the unnecessary
ifdef.

Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220309162454.123006-11-ebiederm@xmission.com


Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>