ata: sata_rcar: add gen[23] fallback compatibility strings

Add fallback compatibility string for R-Car Gen 2 and 3.

In the case of Renesas R-Car hardware we know that there are generations of
SoCs, e.g. Gen 1 and 2. But beyond that its not clear what the relationship
between IP blocks might be. For example, I believe that r8a7790 is older
than r8a7791 but that doesn't imply that the latter is a descendant of the
former or vice versa.

We can, however, by examining the documentation and behaviour of the
hardware at run-time observe that the current driver implementation appears
to be compatible with the IP blocks on SoCs within a given generation.

For the above reasons and convenience when enabling new SoCs a
per-generation fallback compatibility string scheme being adopted for
drivers for Renesas SoCs.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/sata_rcar.c

@@ -858,6 +858,14 @@ static const struct of_device_id sata_rcar_match[] = {
 		.compatible = "renesas,sata-r8a7795",
 		.data = (void *)RCAR_GEN2_SATA
 	},
+	{
+		.compatible = "renesas,rcar-gen2-sata",
+		.data = (void *)RCAR_GEN2_SATA
+	},
+	{
+		.compatible = "renesas,rcar-gen3-sata",
+		.data = (void *)RCAR_GEN2_SATA
+	},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, sata_rcar_match);