arm64: dts: ls1088a: Added dcfg node in ls1088a dtsi

Add debug configuration node(DCFG) in dtsi, helps guts driver to
print the following information in kernel boot log

[    0.526649] Machine: LS1088A RDB Board
[    0.530430] SoC family: QorIQ LS1088A
[    0.534115] SoC ID: svr:0x87030010, Revision: 1.0

Signed-off-by: Amrita Kumari <amrita.kumari@nxp.com>
Signed-off-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>