Missing initialization of udp_tunnel_sock_cfg causes to following
kernel panic, while kernel tries to execute gro_receive().

While being there, we converted udp_port_cfg to use the same
initialization scheme as udp_tunnel_sock_cfg.

------------[ cut here ]------------
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffffffffa0588c50
IP: [<ffffffffa0588c50>] __this_module+0x50/0xffffffffffff8400 [ib_rxe]
PGD 1c09067 PUD 1c0a063 PMD bb394067 PTE 80000000ad5e8163
Oops: 0011 [#1] SMP
Modules linked in: ib_rxe ip6_udp_tunnel udp_tunnel
CPU: 5 PID: 0 Comm: swapper/5 Not tainted 4.7.0-rc3+ #2
Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011
task: ffff880235e4e680 ti: ffff880235e68000 task.ti: ffff880235e68000
RIP: 0010:[<ffffffffa0588c50>]
[<ffffffffa0588c50>] __this_module+0x50/0xffffffffffff8400 [ib_rxe]
RSP: 0018:ffff880237343c80  EFLAGS: 00010282
RAX: 00000000dffe482d RBX: ffff8800ae330900 RCX: 000000002001b712
RDX: ffff8800ae330900 RSI: ffff8800ae102578 RDI: ffff880235589c00
RBP: ffff880237343cb0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800ae33e262
R13: ffff880235589c00 R14: 0000000000000014 R15: ffff8800ae102578
FS:  0000000000000000(0000) GS:ffff880237340000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa0588c50 CR3: 0000000001c06000 CR4: 00000000000006e0
Stack:
ffffffff8160860e ffff8800ae330900 ffff8800ae102578 0000000000000014
000000000000004e ffff8800ae102578 ffff880237343ce0 ffffffff816088fb
0000000000000000 ffff8800ae330900 0000000000000000 00000000ffad0000
Call Trace:
<IRQ>
[<ffffffff8160860e>] ? udp_gro_receive+0xde/0x130
[<ffffffff816088fb>] udp4_gro_receive+0x10b/0x2d0
[<ffffffff81611373>] inet_gro_receive+0x1d3/0x270
[<ffffffff81594e29>] dev_gro_receive+0x269/0x3b0
[<ffffffff81595188>] napi_gro_receive+0x38/0x120
[<ffffffffa011caee>] mlx5e_handle_rx_cqe+0x27e/0x340 [mlx5_core]
[<ffffffffa011d076>] mlx5e_poll_rx_cq+0x66/0x6d0 [mlx5_core]
[<ffffffffa011d7ae>] mlx5e_napi_poll+0x8e/0x400 [mlx5_core]
[<ffffffff815949a0>] net_rx_action+0x160/0x380
[<ffffffff816a9197>] __do_softirq+0xd7/0x2c5
[<ffffffff81085c35>] irq_exit+0xf5/0x100
[<ffffffff816a8f16>] do_IRQ+0x56/0xd0
[<ffffffff816a6dcc>] common_interrupt+0x8c/0x8c
<EOI>
[<ffffffff81061f96>] ? native_safe_halt+0x6/0x10
[<ffffffff81037ade>] default_idle+0x1e/0xd0
[<ffffffff8103828f>] arch_cpu_idle+0xf/0x20
[<ffffffff810c37dc>] default_idle_call+0x3c/0x50
[<ffffffff810c3b13>] cpu_startup_entry+0x323/0x3c0
[<ffffffff81050d8c>] start_secondary+0x15c/0x1a0
RIP  [<ffffffffa0588c50>] __this_module+0x50/0xffffffffffff8400 [ib_rxe]
RSP <ffff880237343c80>
CR2: ffffffffa0588c50
---[ end trace 489ee31fa7614ac5 ]---
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: disabled
---[ end Kernel panic - not syncing: Fatal exception in interrupt
------------[ cut here ]------------

Fixes: 8700e3e7 ("Soft RoCE driver")
Signed-off-by: Yonatan Cohen <yonatanc@mellanox.com>
Reviewed-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>