wifi: iwlwifi: pcie: fix possible NULL pointer dereference

It is possible that iwl_pci_probe() will fail and free the trans,
then afterwards iwl_pci_remove() will be called and crash by trying
to access trans which is already freed, fix it.

iwlwifi 0000:01:00.0: Detected crf-id 0xa5a5a5a2, cnv-id 0xa5a5a5a2
		      wfpm id 0xa5a5a5a2
iwlwifi 0000:01:00.0: Can't find a correct rfid for crf id 0x5a2
...
BUG: kernel NULL pointer dereference, address: 0000000000000028
...
RIP: 0010:iwl_pci_remove+0x12/0x30 [iwlwifi]
pci_device_remove+0x3e/0xb0
device_release_driver_internal+0x103/0x1f0
driver_detach+0x4c/0x90
bus_remove_driver+0x5c/0xd0
driver_unregister+0x31/0x50
pci_unregister_driver+0x40/0x90
iwl_pci_unregister_driver+0x15/0x20 [iwlwifi]
__exit_compat+0x9/0x98 [iwlwifi]
__x64_sys_delete_module+0x147/0x260

Signed-off-by: Daniel Gabay <daniel.gabay@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230413213309.082f6e21341b.I0db21d7fa9a828d571ca886713bd0b5d0b6e1e5c@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>