ARM: tegra: trimslice: add gpio-poweroff node to DT

... and disable tri-state from the pingroup that contains the poweroff
GPIO.
Signed-off-by: NStephen Warren <swarren@nvidia.com>

arch/arm/boot/dts/tegra20-trimslice.dts

@@ -249,6 +249,11 @@
 					"ld23_22";
 				nvidia,pull = <1>;
 			};
+			conf_spif {
+				nvidia,pins = "spif";
+				nvidia,pull = <1>;
+				nvidia,tristate = <0>;
+			};
 		};
 	};
 
@@ -322,6 +327,11 @@
 		bus-width = <4>;
 	};
 
+	poweroff {
+		compatible = "gpio-poweroff";
+		gpios = <&gpio 191 1>; /* gpio PX7, active low */
+	};
+
 	regulators {
 		compatible = "simple-bus";
 		#address-cells = <1>;