net-wireless/hostapd: make USE flag for Suite B

net-wireless/hostapd: make USE flag for Suite B

Suite B functionality in hostapd uses OpenSSL feature unavailable in
LibreSSL. So, enabling that functionality conflicts with using LibreSSL.

Before hostapd-2.9-r2 ebuild, Suite B was disabled.
hostapd-2.9-r2 ebuild has enablied Suite B was unconditionally.
This commit enables it based on suiteb USE flag, which is enabled by
default, and which is declared conflicting with libressl USE flag.

Bug: https://bugs.gentoo.org/710992
Package-Manager: Portage-2.3.66, Repoman-2.3.16
Signed-off-by: Andrey Utkin <andrey_utkin@gentoo.org>