drivers: clock_control: stm32: clear mask bits before setting them

Without this, setting a value of 0 leaves the bits unchanged rather than
zeroing them.

Signed-off-by: Armin Brauns <armin.brauns@embedded-solutions.at>

drivers/clock_control/clock_stm32_ll_common.c

@@ -253,6 +253,8 @@ static inline int stm32_clock_control_configure(const struct device *dev,
 		return 0;
 	}
 
+	sys_clear_bits(DT_REG_ADDR(DT_NODELABEL(rcc)) + STM32_CLOCK_REG_GET(pclken->enr),
+		       STM32_CLOCK_MASK_GET(pclken->enr) << STM32_CLOCK_SHIFT_GET(pclken->enr));
 	sys_set_bits(DT_REG_ADDR(DT_NODELABEL(rcc)) + STM32_CLOCK_REG_GET(pclken->enr),
 		     STM32_CLOCK_VAL_GET(pclken->enr) << STM32_CLOCK_SHIFT_GET(pclken->enr));
 

drivers/clock_control/clock_stm32_ll_h7.c

@@ -414,6 +414,8 @@ static inline int stm32_clock_control_configure(const struct device *dev,
 
 	z_stm32_hsem_lock(CFG_HW_RCC_SEMID, HSEM_LOCK_DEFAULT_RETRY);
 
+	sys_clear_bits(DT_REG_ADDR(DT_NODELABEL(rcc)) + STM32_CLOCK_REG_GET(pclken->enr),
+		       STM32_CLOCK_MASK_GET(pclken->enr) << STM32_CLOCK_SHIFT_GET(pclken->enr));
 	sys_set_bits(DT_REG_ADDR(DT_NODELABEL(rcc)) + STM32_CLOCK_REG_GET(pclken->enr),
 		     STM32_CLOCK_VAL_GET(pclken->enr) << STM32_CLOCK_SHIFT_GET(pclken->enr));
 

drivers/clock_control/clock_stm32_ll_u5.c

@@ -194,6 +194,8 @@ static inline int stm32_clock_control_configure(const struct device *dev,
 		return err;
 	}
 
+	sys_clear_bits(DT_REG_ADDR(DT_NODELABEL(rcc)) + STM32_CLOCK_REG_GET(pclken->enr),
+		       STM32_CLOCK_MASK_GET(pclken->enr) << STM32_CLOCK_SHIFT_GET(pclken->enr));
 	sys_set_bits(DT_REG_ADDR(DT_NODELABEL(rcc)) + STM32_CLOCK_REG_GET(pclken->enr),
 		     STM32_CLOCK_VAL_GET(pclken->enr) << STM32_CLOCK_SHIFT_GET(pclken->enr));