Check AF family prior resolving address and introduce safer rdma_addr_size() variants in ibcore.

Garbage supplied by user will cause to UCMA module provide zero
memory size for memcpy(), because it wasn't checked, it will
produce unpredictable results in rdma_resolve_addr().

There are several places in the ucma ABI where userspace can pass in a
sockaddr but set the address family to AF_IB. When that happens,
rdma_addr_size() will return a size bigger than sizeof struct sockaddr_in6,
and the ucma kernel code might end up copying past the end of a buffer
not sized for a struct sockaddr_ib.

Fix this by introducing new variants

int rdma_addr_size_in6(struct sockaddr_in6 *addr);
int rdma_addr_size_kss(struct __kernel_sockaddr_storage *addr);

that are type-safe for the types used in the ucma ABI and return 0 if the
size computed is bigger than the size of the type passed in. We can use
these new variants to check what size userspace has passed in before
copying any addresses.

Linux commit:
2975d5de6428ff6d9317e9948f0968f7d42e5d74
09abfe7b5b2f442a85f4c4d59ecf582ad76088d7
84652aefb347297aa08e91e283adf7b18f77c2d5

MFC after: 1 week
Sponsored by: Mellanox Technologies