drivers : flash: update way to get flash size

The LL_GetFlashSize function has been removed for
this new HAL H7RS release. Retrieves the value now from
the devicetree using the DT_REG_SIZE macro.

Signed-off-by: Fabrice DJIATSA <[email protected]>

Author: djiatsaf-st

drivers/flash/flash_stm32h7x.c

@@ -45,7 +45,7 @@ LOG_MODULE_REGISTER(LOG_DOMAIN);
 #define REAL_FLASH_SIZE_KB (KB(STM32H7_M4_FLASH_SIZE * 2))
 #endif
 #else
-#define REAL_FLASH_SIZE_KB KB(LL_GetFlashSize())
+#define REAL_FLASH_SIZE_KB DT_REG_SIZE(DT_INST(0, st_stm32_nv_flash))
 #endif
 #define SECTOR_PER_BANK ((REAL_FLASH_SIZE_KB / FLASH_SECTOR_SIZE) / 2)
 #if defined(DUAL_BANK)