ARM: dts: at91: sam9x60ek: classd: pull-down the L1 and L3 lines

The L1 and L3 lines drive NMOS transistors that are OFF with a low level.
On the SAM9X60 EK board, if the pins corresponding to L1 and L3
have pull-ups enabled, there is an extra 2 x 30uA power consumption.
Use pull-downs for these 2 lines to remove the unnecessary power
consumption.

Fixes: 1e5f532c

 ("ARM: dts: at91: sam9x60: add device tree for soc and board")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200615095525.43414-2-codrin.ciubotariu@microchip.com