platform: stm: b_u585i_iot02a: Increase flash non secure access.

Since end of internal flash is not used by secure part, allow
non secure application to use this area.

Change-Id: I1cbe9e103ded3684d08f87e0840ca6fcff2438c0
Signed-off-by: Michel Jaouen <[email protected]>
(cherry picked from 51d7d57)

Author: jamike

platform/ext/target/stm/common/stm32u5xx/secure/target_cfg.c

@@ -46,7 +46,7 @@ REGION_DECLARE(Image$$, TFM_UNPRIV_CODE, $$RO$$Base);
 REGION_DECLARE(Image$$, TFM_APP_RW_STACK_END, $$Base);
 
 #define NON_SECURE_BASE (uint32_t) &REGION_NAME(Load$$LR$$, LR_NS_PARTITION, $$Base)
-#define NON_SECURE_LIMIT (uint32_t)(FLASH_BASE_NS + FLASH_AREA_3_OFFSET + FLASH_AREA_3_SIZE - 1)
+#define NON_SECURE_LIMIT (uint32_t)(FLASH_BASE_NS + FLASH_TOTAL_SIZE - 1)
 #define VENEER_BASE (uint32_t) &REGION_NAME(Load$$LR$$, LR_VENEER, $$Base)
 #define VENEER_LIMIT (uint32_t) &REGION_NAME(Load$$LR$$, LR_VENEER, $$Limit)