Index device tree files

[mgalgs]

It would be nice if I could jump to device tree nodes using global.

An example of a device tree file: https://github.com/lp0/linux/blob/rpi-linear/arch/arm/boot/dts/bcm2835.dtsi

I would assume it would make sense to "namespace" these entries away (prepend dtnode_ to them or something). For example, I'd like to jump to this line if I enter dtnode_pins_gpclk1_a.