ARM: dts: stm32: Drop unused linux,wakeup from touchscreen node on DHCOM SoM

Fix the following dtbs_check warning:
touchscreen@38: 'linux,wakeup' does not match any of the regexes: 'pinctrl-[0-9]+'

Signed-off-by: Marek Vasut <[e-mail]>
Cc: Alexandre Torgue <[e-mail]>
Cc: Patrice Chotard <[e-mail]>
Cc: Patrick Delaunay <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
To: [e-mail]
Signed-off-by: Alexandre Torgue <[e-mail]>

arch/arm/boot/dts/stm32mp15xx-dhcom-pdk2.dtsi

···
 		reg = <0x38>;
 		interrupt-parent = <&gpiog>;
 		interrupts = <2 IRQ_TYPE_EDGE_FALLING>; /* GPIO E */
-		linux,wakeup;
 	};
 };