dt: bindings: vendor-prefix: Add 3 accelerometer vendor prefixes

Recently the kernel has gotten support in the iio subsystem for a number
of new accelerometers from mCube, Memsic and MiraMEMS.

This commit adds the vendor prefixes already used for these vendors
in Documentation/devicetree/bindings/i2c/trivial-devices.txt to
vendor-prefixes.txt.

The "full" company names were taken from the company's websites:
http://www.mcubemems.com/
http://www.memsic.com/
http://www.miramems.com/en/

Signed-off-by: Hans de Goede <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

Documentation/devicetree/bindings/vendor-prefixes.txt

···
 lltc	Linear Technology Corporation
 marvell	Marvell Technology Group Ltd.
 maxim	Maxim Integrated Products
+mcube	mCube
 meas	Measurement Specialties
 mediatek	MediaTek Inc.
 melexis	Melexis N.V.
+memsic	MEMSIC Inc.
 merrii	Merrii Technology Co., Ltd.
 micrel	Micrel Inc.
 microchip	Microchip Technology Inc.
 micron	Micron Technology Inc.
 minix	MINIX Technology Ltd.
+miramems	MiraMEMS Sensing Technology Co., Ltd.
 mitsubishi	Mitsubishi Electric Corporation
 mosaixtech	Mosaix Technologies, Inc.
 moxa	Moxa