geneve: Initialize addr6 with memset

geneve: Initialize addr6 with memset

Clang warns:

drivers/net/geneve.c:428:29: error: suggest braces around initialization
of subobject [-Werror,-Wmissing-braces]
                struct in6_addr addr6 = { 0 };
                                          ^
                                          {}

Rather than trying to appease the various compilers that support the
kernel, use memset, which is unambiguous.

Fixes: c16c7418ecb4 ("geneve: ICMP error lookup handler")
Suggested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>