Add 'vibrator' to list of generic node names

Closes #58

Signed-off-by: Luca Weiss <[email protected]>

Author: z3ntu

source/chapter2-devicetree-basics.rst

@@ -295,6 +295,7 @@ name should be one of the following choices:
    * usb
    * usb-hub
    * usb-phy
+   * vibrator
    * video-codec
    * vme
    * watchdog