Short answer no.
There are 5 LEDs on the Pi
The "ok" light is driven by the SOC and is probablly driven from somewhere in the kernel code, disabling it would be a matter of finding and disabling that code.
The "power" light is not software controllable at all. The only way to disable it would be to pyhically remove either the LED or it's associated series resistor.
The three ethernet LEDs are driven by the ethernet controller. Disabling them would likely involve modifying the ethernet controller driver.