idpf: fix xdp crash in soft reset error path

NULL pointer dereference is reported in cases where idpf_vport_open()
fails during soft reset:

./xdpsock -i <inf> -q -r -N

[ 3179.186687] idpf 0000:83:00.0: Failed to initialize queue ids for vport 0: -12
[ 3179.276739] BUG: kernel NULL pointer dereference, address: 0000000000000010
[ 3179.277636] #PF: supervisor read access in kernel mode
[ 3179.278470] #PF: error_code(0x0000) - not-present page
[ 3179.279285] PGD 0
[ 3179.280083] Oops: Oops: 0000 [#1] SMP NOPTI
...
[ 3179.283997] Workqueue: events xp_release_deferred
[ 3179.284770] RIP: 0010:idpf_find_rxq_vec+0x17/0x30 [idpf]
...
[ 3179.291937] Call Trace:
[ 3179.292392]  <TASK>
[ 3179.292843]  idpf_qp_switch+0x25/0x820 [idpf]
[ 3179.293325]  idpf_xsk_pool_setup+0x7c/0x520 [idpf]
[ 3179.293803]  idpf_xdp+0x59/0x240 [idpf]
[ 3179.294275]  xp_disable_drv_zc+0x62/0xb0
[ 3179.294743]  xp_clear_dev+0x40/0xb0
[ 3179.295198]  xp_release_deferred+0x1f/0xa0
[ 3179.295648]  process_one_work+0x226/0x730
[ 3179.296106]  worker_thread+0x19e/0x340
[ 3179.296557]  ? __pfx_worker_thread+0x10/0x10
[ 3179.297009]  kthread+0xf4/0x130
[ 3179.297459]  ? __pfx_kthread+0x10/0x10
[ 3179.297910]  ret_from_fork+0x32c/0x410
[ 3179.298361]  ? __pfx_kthread+0x10/0x10
[ 3179.298702]  ret_from_fork_asm+0x1a/0x30

Fix the error handling of the soft reset in idpf_xdp_setup_prog() by
restoring the vport->xdp_prog to the old value. This avoids referencing
the orphaned prog that was copied to vport->xdp_prog in the soft reset
and prevents subsequent false positive by idpf_xdp_enabled(). Roll back
the number of queues as well. Also only call put on the program if the
soft reset was successful. Returning an error will trigger the core XDP
stack to handle the put otherwise.

Update the restart check in idpf_xsk_pool_setup() to use IDPF_VPORT_UP bit
instead of netif_running(). The idpf_vport_stop/start() calls will not
update the __LINK_STATE_START bit, making this test a false positive
should the soft reset fail.

Fixes: 3d57b2c00f09 ("idpf: add XSk pool initialization")
Cc: stable@vger.kernel.org
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Joshua Hay <joshua.a.hay@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>