ARM: at91: sama5d3: clock for ssc from rk pin

According to hardware design the clock for SSC device is from rk pin.
Signed-off-by: NBo Shen <voice.shen@atmel.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/boot/dts/sama5d3xmb.dtsi

@@ -32,6 +32,10 @@
 				};
 			};
 
+			ssc0: ssc@f0008000 {
+				atmel,clk-from-rk-pin;
+			};
+
 			/*
 			 * i2c0 conflicts with ISI:
 			 * disable it to allow the use of ISI