ARM: davinci_all_defconfig: Enable CPUFREQ_DT

This sets CONFIG_CPUFREQ_DT=m in davinci_all_defconfig. This is used for
frequency scaling on device tree boards.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>