arm64: zynqmp: Remove information about dma clock on zcu106

Clock setting is not static anymore that's why it depends on firmware setup
that's why remove this comment.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/dts/zynqmp-zcu106-revA.dts

@@ -163,7 +163,6 @@
 	status = "okay";
 };
 
-/* fpd_dma clk 667MHz, lpd_dma 500MHz */
 &fpd_dma_chan1 {
 	status = "okay";
 };