DT: i2c: Deprecate adi,adxl34x compatible string

DT nodes should use the more specific adi,adxl345 and adi,adxl346
compatible values instead. As the ADXL346 is backward-compatible with
the ADXL345, ADXL346 nodes must list both adi,adxl346 and adi,adxl345,
in that order.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>