sparc/defconfigs: Remove CONFIG_IPV6_PRIVACY

Option is long gone, see

  5d9efa7e ("ipv6: Remove privacy config option.")

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: sparclinux@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>