* SAMA5D27 peripheral support - USB Host working
- updated nsh defconfig with vfat for testing USB Host
- sama5d2_xult: USB Host worked.
- ported sam_bringup.c code from sama5d3-xplained
- USB 2.0 HS now working
- other perpherals may work, but haven't been tested
* update license headers to approve NuttX Apache-2.0
patacongo