ipv4: Initialise ifa->hash in inet_alloc_ifa().

Whenever ifa is allocated, we call INIT_HLIST_NODE(&ifa->hash).

Let's move it to inet_alloc_ifa().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20240809235406.50187-5-kuniyu@amazon.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>