Add DT binding documentation for the APMU hardware and add "renesas,apmu"
to the list of enable methods for the ARM cpus.
Signed-off-by: NMagnus Damm <damm+renesas@opensource.se>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NRob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>