There's a history of wanting BSD licenses at Android's inception. If the BSD distributions hadn't run into problems relating to legal battles at the time, Android would be built on Mach with a BSD userland rather than Linux. Additionally, there was more vendor support and drivers for the Linux kernel than Mach. Sadly, for the fledgeling enterprise that was Android, it was better to start from Linux, and use Apache/BSD style licensing and write their own userland.