Add iwn-100 firmware.

The firmware is from the Linux firmware git repository; the intel
licence is the same as other firmware blobs.

Tested: iwn1: <Intel Centrino Wireless-N 100> mem 0xf4800000-0xf4801fff irq 19 at device 0.0 on pci5
Merge remote-tracking branch 'freebsd/master' into hardened/current/intel-smap