STMPE gpio
----------
Required properties:
- compatible: "st,stmpe-gpio"
Optional properties:
- st,norequest-mask: bitmask specifying which GPIOs should _not_ be requestable
due to different usage (e.g. touch, keypad)
Node name must be stmpe_gpio and should be child node of stmpe node to which it
belongs.
Example:
stmpe_gpio {
compatible = "st,stmpe-gpio";
st,norequest-mask = <0x20>; //gpio 5 can't be used
};