of: Add vendor prefix for Si-En Technology

Si-En Technology is a fabless design house which offers
audio amplifiers, LED drivers and sensors.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -205,6 +205,7 @@ seagate	Seagate Technology PLC
 semtech	Semtech Corporation
 sgx	SGX Sensortech
 sharp	Sharp Corporation
+si-en	Si-En Technology Ltd.
 sigma	Sigma Designs, Inc.
 sil	Silicon Image
 silabs	Silicon Laboratories