omap cpufreq driver in multi-platform kernels

[Rob Herring]

Kevin, Tony, Paul,

The omap cpufreq driver causes problems in multi-platform kernels
because it unconditionally registers with the cpufreq core and does not
check sufficiently that it is running on an omap platform. So on a
kernel with highbank and omap drivers booted on highbank, the
cpufreq-cpu0 driver fails to init. Any suggestions for how to fix? For
DT this could just be several of_machine_is_compatible checks, but I'm
not really sure for non-DT. Converting the driver to a platform driver
would be another option.

This will also affect other cpufreq-cpu0 users like iMX. And I'd guess
there may be other ARM cpufreq drivers that will cause the same issue.

Rob