kernel: add linux 4.9 support

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Tim Harvey <tharvey@gateworks.com> [fixes]

target/linux/generic/patches-4.9/130-add-linux-spidev-compatible-si3210.patch

@@ -0,0 +1,15 @@
+Add the linux,spidev compatible in spidev
+Several device in ramips have this binding in the dts
+
+Signed-off-by: Giuseppe Lippolis <giu.lippolis@gmail.com>
+---
+--- a/drivers/spi/spidev.c
++++ b/drivers/spi/spidev.c
+@@ -696,6 +696,7 @@ static struct class *spidev_class;
+ static const struct of_device_id spidev_dt_ids[] = {
+ 	{ .compatible = "rohm,dh2228fv" },
+ 	{ .compatible = "lineartechnology,ltc2488" },
++	{ .compatible = "siliconlabs,si3210" },
+ 	{},
+ };
+ MODULE_DEVICE_TABLE(of, spidev_dt_ids);