tests: drivers: nucleo_u385rg_q: update i2c tests drivers

Enable and add pinctrl for the I2C3 node, and disable the SPI1 node
since it is enabled by default on this board (via the Arduino connector),
which causes a conflict with the I2C3 pinctrl configuration.

Signed-off-by: Ulrich KAMDEM <kamdemulricharmel@gmail.com>

Author: ulrich-a11-y

tests/drivers/i2c/i2c_target_api/boards/nucleo_u385rg_q.overlay

@@ -14,6 +14,10 @@
  */
 
 &i2c3 {
+	pinctrl-0 = <&i2c3_scl_pa7 &i2c3_sda_pc1>;
+	pinctrl-names = "default";
+	status = "okay";
+
 	eeprom0: eeprom@54 {
 		compatible = "zephyr,i2c-target-eeprom";
 		reg = <0x54>;
@@ -28,3 +32,7 @@
 		size = <256>;
 	};
 };
+
+&spi1 {
+	status = "disabled";
+};