ARM: dts: renesas: iwg22d-sodimm: Fix stmpe node names

make dtbs_check:

    arch/arm/boot/dts/renesas/r8a7745-iwg22d-sodimm.dtb: stmpe811@44: 'stmpe_touchscreen' does not match any of the regexes: 'pinctrl-[0-9]+'
	    from schema $id: http://devicetree.org/schemas/mfd/st,stmpe.yaml#
    arch/arm/boot/dts/renesas/r8a7745-iwg22d-sodimm-dbhd-ca.dtb: stmpe811@44: 'stmpe_touchscreen' does not match any of the regexes: 'pinctrl-[0-9]+'
	    from schema $id: http://devicetree.org/schemas/mfd/st,stmpe.yaml#

Fix this by using recommended node names for the STMicroelectronics Port
Expander (STMPE) device node and its subnode.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/40536ce7ca01e5acc9ed1d595f0e3a720eeb78d7.1698228434.git.geert+renesas@glider.be

arch/arm/boot/dts/renesas/r8a7745-iwg22d-sodimm.dts

@@ -182,7 +182,7 @@ sgtl5000: codec@a {
 		VDDIO-supply = <&reg_3p3v>;
 	};
 
-	stmpe811@44 {
+	port-expander@44 {
 		compatible = "st,stmpe811";
 		reg = <0x44>;
 		interrupt-parent = <&gpio4>;
@@ -197,7 +197,7 @@ stmpe811@44 {
 		/* internal ADC reference */
 		st,ref-sel = <0>;
 
-		stmpe_touchscreen {
+		touchscreen {
 			compatible = "st,stmpe-ts";
 			/* 8 sample average control */
 			st,ave-ctrl = <3>;