ARM: dts: stm32: Fix touchscreen node on dhcom-pdk2

Fix make dtbs_check warning:
arch/arm/boot/dts/stm32mp157c-dhcom-pdk2.dt.yaml:0:0: /soc/i2c@40015000/polytouch@38: failed to match any schema with compatible: ['edt,edt-ft5x06']
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

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

@@ -182,8 +182,8 @@ sgtl5000_rx_endpoint: endpoint@1 {
 
 	};
 
-	polytouch@38 {
-		compatible = "edt,edt-ft5x06";
+	touchscreen@38 {
+		compatible = "edt,edt-ft5406";
 		reg = <0x38>;
 		interrupt-parent = <&gpiog>;
 		interrupts = <2 IRQ_TYPE_EDGE_FALLING>; /* GPIO E */