spi: dw: Add SoC-specific compatible strings

This adds SoC-specific compatible strings to all users of the designware
spi device. This will allow for the correct driver to be selected for each
device. Where it is publicly documented, a compatible string for the
specific device version has also been added. Devices without
publicly-documented device versions include MSCC SoCs, and Arc Socs. All
compatible strings except those for SoCFPGAs and some of the versioned
strings have been taken from Linux.

Since SSI_MAX_XFER_SIZE is determined at runtime, this is not strictly
necessary. However, it is a good cleanup and brings things closer to Linux.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Tested-by Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/arch/arm/dts/socfpga.dtsi b/arch/arm/dts/socfpga.dtsi
index eda558f..ff79d33 100644
--- a/arch/arm/dts/socfpga.dtsi
+++ b/arch/arm/dts/socfpga.dtsi
@@ -804,7 +804,8 @@
 		};
 
 		spi0: spi@fff00000 {
-			compatible = "snps,dw-apb-ssi";
+			compatible = "altr,socfpga-spi", "snps,dw-apb-ssi-3.20",
+				     "snps,dw-apb-ssi";
 			#address-cells = <1>;
 			#size-cells = <0>;
 			reg = <0xfff00000 0x1000>;
@@ -816,7 +817,8 @@
 		};
 
 		spi1: spi@fff01000 {
-			compatible = "snps,dw-apb-ssi";
+			compatible = "altr,socfpga-spi", "snps,dw-apb-ssi-3.20",
+				     "snps,dw-apb-ssi";
 			#address-cells = <1>;
 			#size-cells = <0>;
 			reg = <0xfff01000 0x1000>;