Add Renesas R8A77970/Eagle board support

Hello.

Here's the set of 8 patches against Simon Horman's 'renesas.git' repo's
'renesas-devel-20170915-v4.13' tag. I'm adding the device tree support for the R8A77970-based Eagle board. Already merged patches will not be reposted. The necessary SYS-DMAC, [H]SCIF, and EtherAVB bindings updates have been posted earlier.

[1/8] soc: renesas: rcar-sysc: add R8A77970 support [2/8] arm64: dts: renesas: initial R8A77970 SoC device tree [3/8] arm64: dts: renesas: r8a77970: add SYS-DMAC support [4/8] arm64: dts: renesas: r8a77970: add [H]SCIF support [5/8] arm64: dts: renesas: r8a77970: add EtherAVB support [6/8] arm64: renesas: document Eagle board bindings [7/8] arm64: dts: renesas: initial Eagle board device tree [8/8] arm64: dts: renesas: eagle: add EtherAVB support

WBR, Sergei