Unconditionally enable the clocks for all imx6 devices that we have drivers
for, or that are required to run the chip (such as busses).  Turn off all
the devices we don't yet have drivers for.

Some day we will have a fully functional imx6 clock driver so that we can
manage clocks based on fdt data.  This will have to do until then.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273514 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f