ARM: dts: at91: fixes dbgu pinctrl, set pullup on rx, clear pullup on tx

Remove pullup on dbgu DTXD signal, it is a push-pull output thus the
pullup is pointless.

Add pullup on dbgu DRXD signal, it prevents the DRXD signal to be left
floating and so consuming a useless extra amount of power in crowbarred
state if nothing is externally connected to dbgu.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

arch/arm/boot/dts/at91sam9260.dtsi

@@ -412,8 +412,8 @@
 				dbgu {
 					pinctrl_dbgu: dbgu-0 {
 						atmel,pins =
-							<AT91_PIOB 14 AT91_PERIPH_A AT91_PINCTRL_NONE	/* PB14 periph A */
-							 AT91_PIOB 15 AT91_PERIPH_A AT91_PINCTRL_PULL_UP>;	/* PB15 periph with pullup */
+							<AT91_PIOB 14 AT91_PERIPH_A AT91_PINCTRL_PULL_UP
+							 AT91_PIOB 15 AT91_PERIPH_A AT91_PINCTRL_NONE>;
 					};
 				};