Hello Joshua Hong,
If you want to run Android on one of NXP’s i.MX6 EVKs and SABRE boards, you may download the available BSPs which include an End User License Agreement, but no further license is needed.
If you plan to run Android on your own i.MX6 application, you may use Android Open Source Project which also comes with its own license agreement.
If you want to include Android on a finished product, however, you would need to contact Google for more information on licensing.
I hope this helps!
Regards,