net/mlx5: CT: Change idr to xarray to protect parallel tuple id allocation

After allowing parallel tuple insertion, we get the following trace:

[ 5505.142249] ------------[ cut here ]------------
[ 5505.148155] WARNING: CPU: 21 PID: 13313 at lib/radix-tree.c:581 delete_node+0x16c/0x180
[ 5505.295553] CPU: 21 PID: 13313 Comm: kworker/u50:22 Tainted: G           OE     5.6.0+ #78
[ 5505.304824] Hardware name: Supermicro Super Server/X10DRT-P, BIOS 2.0b 03/30/2017
[ 5505.313740] Workqueue: nf_flow_table_offload flow_offload_work_handler [nf_flow_table]
[ 5505.323257] RIP: 0010:delete_node+0x16c/0x180
[ 5505.349862] RSP: 0018:ffffb19184eb7b30 EFLAGS: 00010282
[ 5505.356785] RAX: 0000000000000000 RBX: ffff904ac95b86d8 RCX: ffff904b6f938838
[ 5505.365190] RDX: 0000000000000000 RSI: ffff904ac954b908 RDI: ffff904ac954b920
[ 5505.373628] RBP: ffff904b4ac13060 R08: 0000000000000001 R09: 0000000000000000
[ 5505.382155] R10: 0000000000000000 R11: 0000000000000040 R12: 0000000000000000
[ 5505.390527] R13: ffffb19184eb7bfc R14: ffff904b6bef5800 R15: ffff90482c1203c0
[ 5505.399246] FS:  0000000000000000(0000) GS:ffff904c2fc80000(0000) knlGS:0000000000000000
[ 5505.408621] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5505.415739] CR2: 00007f5d27006010 CR3: 0000000058c10006 CR4: 00000000001626e0
[ 5505.424547] Call Trace:
[ 5505.428429]  idr_alloc_u32+0x7b/0xc0
[ 5505.433803]  mlx5_tc_ct_entry_add_rule+0xbf/0x950 [mlx5_core]
[ 5505.441354]  ? mlx5_fc_create+0x23c/0x370 [mlx5_core]
[ 5505.448225]  mlx5_tc_ct_block_flow_offload+0x874/0x10b0 [mlx5_core]
[ 5505.456278]  ? mlx5_tc_ct_block_flow_offload+0x63d/0x10b0 [mlx5_core]
[ 5505.464532]  nf_flow_offload_tuple.isra.21+0xc5/0x140 [nf_flow_table]
[ 5505.472286]  ? __kmalloc+0x217/0x2f0
[ 5505.477093]  ? flow_rule_alloc+0x1c/0x30
[ 5505.482117]  flow_offload_work_handler+0x1d0/0x290 [nf_flow_table]
[ 5505.489674]  ? process_one_work+0x17c/0x580
[ 5505.494922]  process_one_work+0x202/0x580
[ 5505.500082]  ? process_one_work+0x17c/0x580
[ 5505.505696]  worker_thread+0x4c/0x3f0
[ 5505.510458]  kthread+0x103/0x140
[ 5505.514989]  ? process_one_work+0x580/0x580
[ 5505.520616]  ? kthread_bind+0x10/0x10
[ 5505.525837]  ret_from_fork+0x3a/0x50
[ 5505.570841] ---[ end trace 07995de9c56d6831 ]---

This happens from parallel deletes/adds to idr, as idr isn't protected.
Fix that by using xarray as the tuple_ids allocator instead of idr.

Fixes: 7da182a9

 ("netfilter: flowtable: Use work entry per offload command")
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>