cpufreq: dt: Don't use generic platdev driver for ti-cpufreq platforms

Some TI platforms, specifically those in the am33xx, am43xx, dra7xx, and
am57xx families of SoCs can make use of the ti-cpufreq driver to
selectively enable OPPs based on the exact configuration in use. The
ti-cpufreq is given the responsibility of creating the cpufreq-dt
platform device when the driver is in use so drop am33xx and dra7xx
from the cpufreq-dt-platdev driver so it is not created twice.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>