Add relnotes item for 8.1R (first round):

Add relnotes item for 8.1R (first round):
        ddb(4) show mount improved,
        fcntl(2) F_READAHEAD and F_RDAHEAD added,
        lindev(4) added,
        more dtrace probes,
        SMP support in PowerPC G5,
        ULE %CPU fix,
        VIMAGE + SCTP build fix,
        vfs.root.mountfrom space-separated list support added,
        loader(8) memory range selection improved,
        zfsloader added,
        zfsboot and gptboot added,
        adb(4) supports taps on ADB touchpad,
        apt(4) added,
        uart(4) NetMos NM9865 support added,
        bge(4) 5761, 5784, 57780 support added,
        cxgb(4) updated to T3 firmware 7.8.0,
        msk(4) 88E8042, 88E8057 and DGE-560SX support added,
        re(4) unnecessary reinitialization eliminated,
        tsec(4) now supports ALTQ,
        urtw(4) now supports RTL8187B,
        net.inet.ipcomp.ipcomp_enable=1 by default,
        IPV6_V6ONLY by default for IPv6 sockets in Linux emulation,
        gmirror(8) priority change support,
        gmirror(8) "load" balancing algorithm improved and now used as default,
        "option ATA_CAM" added,
        ata(4) fix for interrupt storms/command timeouts added,
        ata(4) umass support removed,
        ahd(4) error counter improved,
        cam(3) SATA/PATA support improved,
        bsnmpd(1) high CPU load issue fixed,
        bzip2(1) multi-session bzip2 file handling fixed,
        ee(1) crach fixed,
        factor(6) performance issue fixed,
        fetch(1) NO_PROXY handling fixed,
        ifconfig(8) now supports NDP flag handling,
        ntpd(8) no longer attempts to bind IPv6 anycast addresses,
        unifdef(1) updated to 1.188,
        ENOTCAPABLE new errno,
        rc.d/static_arp added, and
        ISC BIND 9.6.1-P2.

git-svn-id: svn://svn.freebsd.org/base/stable/8@210339 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f