ARM: bcm2835: add I2C controllers to DT

The BCM2835 has 3 identical I2C controllers. Instantiate them all in the
SoC .dtsi file, and enable the relevant two in the Raspberry Pi board
.dts file.

Note that on the Raspberry Pi Model B revision 1, I2C0 is connected to
the general-purpose expansion header, and I2C1 is connected to the camera
connector. Revision 2 of the board swaps these assignments:-(

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
diff --git a/arch/arm/boot/dts/bcm2835-rpi-b.dts b/arch/arm/boot/dts/bcm2835-rpi-b.dts
index 0544ef8..aafda17 100644
--- a/arch/arm/boot/dts/bcm2835-rpi-b.dts
+++ b/arch/arm/boot/dts/bcm2835-rpi-b.dts
@@ -25,6 +25,16 @@
 	};
 };
 
+&i2c0 {
+	status = "okay";
+	clock-frequency = <100000>;
+};
+
+&i2c1 {
+	status = "okay";
+	clock-frequency = <100000>;
+};
+
 &sdhci {
 	status = "okay";
 	bus-width = <4>;