Fix the led 'gpios' definition to match the description on
sys/boot/fdt/dts/bindings-gpio.txt.  Make the led pin an output, add the
missing flag field.  No functional change (gpioled(4) isn’t supported on
FDT systems yet).

Approved by:	adrian (mentor)
Connect the two recently added man pages to the system's install process.

Approved by:	adrian (mentor)