arm: dts: Add Arm FVP Fastmodel RevC .dts files from Linux

The Arm Fixed Virtual Platform (FVP) is a software model for an
artificial ARM platform, it is available for free on the Arm website[1].

Add the devicetree files for the latest RevC version, as we will need
them to enable OF_CONTROL for the vexpress_aemv8a_semi board.

This is a verbatim copy of the respective files from Linux v5.17-rc6,
which is unchanged from the v5.16 release.

[1] https://developer.arm.com/tools-and-software/simulation-models/fast-models



Signed-off-by: Andre Przywara <andre.przywara@arm.com>