DT: pci: rcar-pci: document R8A77990 bindings

Document the R-Car E3 (R8A77990) SoC in the R-Car PCIe bindings.
Signed-off-by: Tho Vu <tho.vu.wh@rvc.renesas.com>
Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-renesas-soc@vger.kernel.org

Documentation/devicetree/bindings/pci/rcar-pci.txt

@@ -9,6 +9,7 @@ compatible: "renesas,pcie-r8a7743" for the R8A7743 SoC;
 	    "renesas,pcie-r8a7795" for the R8A7795 SoC;
 	    "renesas,pcie-r8a7796" for the R8A7796 SoC;
 	    "renesas,pcie-r8a77980" for the R8A77980 SoC;
+	    "renesas,pcie-r8a77990" for the R8A77990 SoC;
 	    "renesas,pcie-rcar-gen2" for a generic R-Car Gen2 or
 				     RZ/G1 compatible device.
 	    "renesas,pcie-rcar-gen3" for a generic R-Car Gen3 compatible device.