entry: Fix boot for !CONFIG_GENERIC_ENTRY

A copy-pasta mistake tries to set SYSCALL_WORK flags instead of TIF
flags for !CONFIG_GENERIC_ENTRY.  Also, add safeguards to catch this at
compilation time.

Fixes: 3136b93c ("entry: Expose helpers to migrate TIF to SYSCALL_WORK flags")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/87a6v8qd9p.fsf_-_@collabora.com