arm64: dts: r8a7795: Remove FCP SoC-specific compatible strings

The SoC-specific compatible strings have been removed from the FCP DT
bindings, removed them from the device tree.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>