arm64: zynqmp: Add u-boot,dm-pre-reloc to clk300 node

This node is used by qspi driver for supporting qspi boot mode in SPL.

Similar changes have beeen done by commit a9022b01
("ARM64: zynqmp: Add u-boot,dm-pre-reloc to clk nodes")

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