dt-bindings: serial: renesas,scifa: Remove part numbers from comments

The conversion to json-schema accidentally retained some SoC part
numbers in comments for compatible values.  Drop them, as they're part
of the compatible values anyway.

Fixes: 384d00fa ("dt-bindings: serial: sh-sci: Convert to json-schema")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>