ARM: socfpga: dts: Move common nodes to cyclone5 dtsi

The current socfpga_cyclone5.dts describes the Altera Cyclone5 SoC Development
Kit. The Cyclone5 includes a SoCFPGA, which itself can be included in other
SoC+FPGA combinations.

Instead of having to describe all Cyclone5 common nodes in every board specific
dts, move socfpga_cyclone5.dts to a dtsi and include this in a new dts for the
Development Kit.

[Dinh Nguyen] - Changed to 115200 for baudrate in dts bootargs

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Dinh Nguyen <dinguyen@altera.com>