powerpc/85xx: add Freescale P5040 SOC and SEC v5.2 device trees

Add device tree (dtsi) files for the Freescale P5040 SOC.  Since this
SOC introduces SEC v5.2, add the dtsi file for that also.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>