Fix Intel Centrino Advanced 6235 missing subdevice id 0x5260
booting dfly-5.2.2 on a thinkpad t431s with an intel centrino advanced 6235 wireless card fails with the following message
iwn0: adapter type id : 0x088f sub id :0x5260 rev 11 not supported (subdevice)
iwn0: could not attach device, error 45
if_iwn_devid.h  is missing a subdevice id 0x5260 definition for 6x35 devices. Therefore, in if_iwn.c  at iwn_config_specific function, lines 910 to 928, the default case is hit which throws the error.
as the corresponding firmware (iwlwifi-6000g2b-18.104.22.168) is up-to-date the problem can be fixed by just adding the missing subdevice id value to the 6x35 definitions in if_iwn_devid.h  plus adding a corresponding case-check to the switch statement in iwn_config_specific function in if_iwn.c .
first, FreeBSD version already contains the missing subdevice id definition, see  line 173.
second, after applying the patches and recompiling the kernel the aforementioned error at boot time is gone. Also, the interface (iwn0) gets listed correctly and connecting to wifi as well as transmitting and receiving packets is working.
- File 0001-add-subdevice-id-0x5260-for-iwn-6035-series.patch 0001-add-subdevice-id-0x5260-for-iwn-6035-series.patch added
re-submitted patch file with corrected author information