dt-bindings: add ebang vendor prefix

Add vendor prefix for Zhejiang Ebang Communication Co., Ltd.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210120194033.26970-2-michael@walle.cc


Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>