Commit f37b953e (ntdll: Support both HP-UX-like libunwind and LLVM
libunwind error codes., 2021-12-10) made an unsuccessful attempt to fix
UNW_ENOINFO detection on LLVM libunwind.  It turns out that UNW_ENOINFO
is actually negative in LLVM, so there's no need to flip the sign.

Fix this by flipping the return value sign only when UNW_ENOINFO < 0
(LLVM libunwind), and then comparing it against the negated error code.
Overall, all flavours of libunwind return a negative value on error.
Signed-off-by: Jinoh Kang <jinoh.kang.kr@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>