ARM: dts: at91: sama5d2_xplained: classd: pull-down the R1 and R3 lines

The R1 and R3 lines drive NMOS transistors that are OFF with a low level.
On the SAMA5D2 Xplained board, if the pins corresponding to R1 and R3
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: b133ca7a ("ARM: dts: at91: sama5d2_xplained: add pin muxing and enable classd")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200615095525.43414-1-codrin.ciubotariu@microchip.com