ARM64: zynqmp: Add clocks for LPDDMA

Zynqmp DMA driver expects two clocks (main clock and apb clock)
For LPDDMA channels the two clocks are missing in the
Dma node resulting probe failure.

xilinx-zynqmp-dma ffa80000.dma: main clock not found.
xilinx-zynqmp-dma ffa80000.dma: Probing channel failed
xilinx-zynqmp-dma: probe of ffa80000.dma failed with error -2

This patch fixes this issue.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>