TI-NSPIRE calculators

Required properties:
- compatible: Compatible property value should contain "ti,nspire".
	CX models should have "ti,nspire-cx"
	Touchpad models should have "ti,nspire-tp"
	Clickpad models should have "ti,nspire-clp"

Example:

/ {
	model = "TI-NSPIRE CX";
	compatible = "ti,nspire-cx";
	...
