ipv4: fib: Allocate fib_info_hash[] and fib_info_laddrhash[] by kvcalloc().

ipv4: fib: Allocate fib_info_hash[] and fib_info_laddrhash[] by kvcalloc().

Both fib_info_hash[] and fib_info_laddrhash[] are hash tables for
struct fib_info and are allocated by kvzmalloc() separately.

Let's replace the two kvzmalloc() calls with kvcalloc() to remove
the fib_info_laddrhash pointer later.

Note that fib_info_hash_alloc() allocates a new hash table based on
fib_info_hash_bits because we will remove fib_info_hash_size later.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250228042328.96624-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>