dt-bindings: pwm: rcar: Add bindings for R-Car E3 support

This patch adds bindings for R-Car E3. No driver update is needed.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt

@@ -12,6 +12,7 @@ Required Properties:
  - "renesas,pwm-r8a7795": for R-Car H3
  - "renesas,pwm-r8a7796": for R-Car M3-W
  - "renesas,pwm-r8a77965": for R-Car M3-N
+ - "renesas,pwm-r8a77990": for R-Car E3
  - "renesas,pwm-r8a77995": for R-Car D3
 - reg: base address and length of the registers block for the PWM.
 - #pwm-cells: should be 2. See pwm.txt in this directory for a description of