Remove workaround for kernel IPV6_MULTICAST_HOPS bug

This has been fixed since Linux 2.6.

    ipv6: Fix default multicast hops setting.

    As per RFC 3493 the default multicast hops setting
    for a socket should be "1" just like ipv4.

    Ironically we have a IPV6_DEFAULT_MCASTHOPS macro
    it just wasn't being used.

    Reported-by: Elliot Hughes <enh@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

    https://kernel.googlesource.com/pub/scm/linux/kernel/git/stable/linux-stable/+/f935aa9e99d6ec74a50871c120e6b21de7256efb

Test: CTS
Bug: 32071916
Change-Id: I0e25a86a2ff12a7e77074636bc99a281cfb57dbe