tests: drivers: i2c: i2c_target_api: update i2c_target_api test

- add overlays and kconfig files for nucleo_c071rb board.
- update testcase.yaml for CI integration.

Signed-off-by: Fabrice DJIATSA <fabrice.djiatsa-ext@st.com>

Author: djiatsaf-st

tests/drivers/i2c/i2c_target_api/boards/nucleo_c071rb.conf

@@ -0,0 +1,2 @@
+CONFIG_I2C_STM32_INTERRUPT=y
+CONFIG_I2C_VIRTUAL=n

tests/drivers/i2c/i2c_target_api/boards/nucleo_c071rb.overlay

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2025 STMicroelectronics
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* I2C bus pins are exposed on the ST morpho header.
+ *
+ *  Bus        SDA               SCL
+ *          Pin   Hdr         Pin   Hdr
+ *  i2c1    PB9   CN5:9      PB8   CN5:10
+ *  i2c2    PA6   CN5:5      PA7   CN5:4
+ *
+ * Short Pin PB9 to PA6, and PB8 to PA7, for the test to pass.
+ */
+
+&i2c1 {
+	eeprom0: eeprom@54 {
+		compatible = "zephyr,i2c-target-eeprom";
+		reg = <0x54>;
+		size = <256>;
+	};
+};
+
+&i2c2 {
+	eeprom1: eeprom@56 {
+		compatible = "zephyr,i2c-target-eeprom";
+		reg = <0x56>;
+		size = <256>;
+	};
+};

tests/drivers/i2c/i2c_target_api/testcase.yaml

@@ -18,6 +18,7 @@ tests:
       - stm32f3_disco
       - stm32h573i_dk
       - stm32u083c_dk
+      - nucleo_c071rb
       - nucleo_g071rb
       - nucleo_f207zg
       - nucleo_f401re