arm64: dts: altera: socfpga_stratix10: move clocks out of soc node

The clocks are not part of the SoC but provided on the board
(external oscillators). Moving them out of soc node.

Signed-off-by: Niravkumar L Rabara <niravkumar.l.rabara@intel.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>