Minor fix to process_ip_header

Minor fix to process_ip_header

Removed if-guard checking if any feature is
enabled before performing per-feature check.
It doesn't save us much but instead introduces
uneeded complexity.

While at it, fixed a typo IMCP -> ICMP for defined
PIPV6_ICMP_NOHOST_CLIENT and PIPV6_ICMP_NOHOST_SERVER
macros.

Fixes: Trac https://community.openvpn.net/openvpn/ticket/269
Change-Id: I4b5e8357d872c920efdb64632e9bce72cebee202
Signed-off-by: Gianmarco De Gregori <gianmarco@mandelbit.com>
Acked-by: Arne Schwabe <arne-openvpn@rfc2549.org>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Message-Id: <20240307124616.16358-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg28345.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>