airoha/dts: fix en7581 pinctrl regions sizes

We map 8 IOMUX control registers of 32-bit size (IOMUX1-IOMUX7 and
IOMUX_RESERVE1), so it should takes 0x20 bytes, but dts reserve only
0x1C bytes in i/o address space. This is definitely a bug.

airoha/dts/en7581-base.dtsi

@@ -436,7 +436,7 @@
 		//   2) Please keep in sync iomem areas used by this driver with
 		//	is_pinctrl_reg() function from the "ecnt-scu" driver.
 		// --------------------------------------------------------------------
-		reg = <0x0 0x1fa20214 0x0 0x1C>, /* IOMUX Control Registers */
+		reg = <0x0 0x1fa20214 0x0 0x20>, /* IOMUX Control Registers */
 			<0x0 0x1fa2001C 0x0 0x18>, /* IO TX Driving Control Registers */
 			<0x0 0x1fa20044 0x0 0x18>, /* IO Pull up/down Control Registers */
 			<0x0 0x1fa2027C 0x0 0x8>;  /* LED Mapping Register */