dt-bindings: clk: armada3700: document the PCIe clock

Add a reference to the missing PCIe clock managed by this IP. The
clock resides in the south bridge.

Signed-off-by: Miquel Raynal <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Stephen Boyd <[email protected]>

Author: miquelraynal

Documentation/devicetree/bindings/clock/armada3700-periph-clock.txt

@@ -46,6 +46,7 @@ ID	Clock name	Description
 10	sdio		SDIO
 11	usb32-sub2-sys	USB 2 clock
 12	usb32-ss-sys	USB 3 clock
+13	pcie		PCIe controller
 
 Required properties: