ARM: dts: am335x-icev2: Disable Industrial I/O LEDs and fix naming

The LEDs tied to the Industrial I/O output pins are meant for providing
status feed-back and are not the primary use for the pins. Disable
this use by default. Also unify the LED naming across IDK platforms.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>