devicetree: add DPTechnics vendor id

Please see https://www.dptechnics.com/contact

 for details.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Cc: Daan Pape <daan@dptechnics.com>
Cc: devicetree@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12885/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>