cpufreq: dt: Add support for r8a7743 and r8a7745

Add the compatible strings for supporting the generic cpufreq driver on
the Renesas RZ/G1M (r8a7743) and RZ/G1E (r8a7745) SoCs.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>