Initial board support for the Radxa Rock.
change-param: make sure all commands succeed.
change-param.sh: fix the sed command.
Radxa: improve the recovery mode instructions.
Radxa: use tmpfs.
Radxa: add support for the Lite version

The boot loader on the Radxa Rock is very limited and at this point it's not
possible to select a DTS.  For this reason, FreeBSD has two kernel
configuration files which include a static DTS.
Radxa: use the KERNCONF variable for kernel.bin
Radxa: remove an extra comma in fstab
Radxa: add TODO comments
Merge pull request #68 from rpaulo/master

Initial support for the Radxa Rock