ARM: dts: imx6q-apalis: Disable stmpe touchscreen

Unify its label with other toradex SoM dtbs.
This allows to enable it in an overlay per the current
system configuration.

Signed-off-by: Oleksandr Suvorov <[e-mail]>
Signed-off-by: Max Krummenacher <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/imx6qdl-apalis.dtsi

···
 		/* ADC conversion time: 80 clocks */
 		st,sample-time = <4>;
 
-		stmpe_touchscreen: stmpe_touchscreen {
+		stmpe_ts: stmpe_touchscreen {
 			compatible = "st,stmpe-ts";
 			/* 8 sample average control */
 			st,ave-ctrl = <3>;
···
 			st,settling = <3>;
 			/* 5 ms touch detect interrupt delay */
 			st,touch-det-delay = <5>;
+			status = "disabled";
 		};
 
 		stmpe_adc: stmpe_adc {