tests: clock_control: stm32f3: Fix test overlay

A second, faulty, configuration was provided for rcc node, which made
the test failing.

Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
diff --git a/tests/drivers/clock_control/stm32_clock_configuration/stm32_common_devices/boards/f3_i2c1_hsi.overlay b/tests/drivers/clock_control/stm32_clock_configuration/stm32_common_devices/boards/f3_i2c1_hsi.overlay
index a6a5f63..610cd80 100644
--- a/tests/drivers/clock_control/stm32_clock_configuration/stm32_common_devices/boards/f3_i2c1_hsi.overlay
+++ b/tests/drivers/clock_control/stm32_clock_configuration/stm32_common_devices/boards/f3_i2c1_hsi.overlay
@@ -62,13 +62,6 @@
 	clock-frequency = <DT_FREQ_M(32)>;
 };
 
-&rcc {
-	clocks = <&pll>;
-	clock-frequency = <DT_FREQ_M(64)>;
-	ahb-prescaler = <1>;
-	apb1-prescaler = <2>;
-};
-
 &i2c1 {
 	/delete-property/ clocks;
 	clocks = <&rcc STM32_CLOCK_BUS_APB1 0x00200000>,