drivers: flash: stm32 flash register name for the stm32h7RS serie

Adapt the stm32 flash driver for the stm32h7rs serie where some
bit of the FLASH registers are named differently from stm32h7 serie.

Signed-off-by: Francois Ramu <francois.ramu@st.com>

drivers/flash/flash_stm32h7x.c

@@ -85,8 +85,11 @@ static __unused int write_optb(const struct device *dev, uint32_t mask,
 	}
 
 	regs->OPTCR = (regs->OPTCR & ~mask) | value;
+#ifdef CONFIG_SOC_SERIES_STM32H7RSX
+	regs->OPTCR |= FLASH_OPTCR_PG_OPT;
+#else
 	regs->OPTCR |= FLASH_OPTCR_OPTSTART;
-
+#endif /* CONFIG_SOC_SERIES_STM32H7RSX */
 	/* Make sure previous write is completed. */
 	barrier_dsync_fence_full();
 
@@ -121,8 +124,13 @@ int flash_stm32_option_bytes_lock(const struct device *dev, bool enable)
 	if (enable) {
 		regs->OPTCR |= FLASH_OPTCR_OPTLOCK;
 	} else if (regs->OPTCR & FLASH_OPTCR_OPTLOCK) {
+#ifdef CONFIG_SOC_SERIES_STM32H7RSX
+		regs->OPTKEYR = FLASH_OPTKEY1;
+		regs->OPTKEYR = FLASH_OPTKEY2;
+#else
 		regs->OPTKEYR = FLASH_OPT_KEY1;
 		regs->OPTKEYR = FLASH_OPT_KEY2;
+#endif /* CONFIG_SOC_SERIES_STM32H7RSX */
 	}
 
 	if (enable) {