bsp_mcu_device_pn_cfg.h has the R6M5 variant with 1.5 MB flash

bsp_mcu_device_pn_cfg.h
```
/* generated configuration header file - do not edit */
#ifndef BSP_MCU_DEVICE_PN_CFG_H_
#define BSP_MCU_DEVICE_PN_CFG_H_
#define BSP_MCU_R7FA6M5AG2CBG
#define BSP_MCU_FEATURE_SET ('A')
#define BSP_ROM_SIZE_BYTES (1572864)
#define BSP_RAM_SIZE_BYTES (524288)
#define BSP_DATA_FLASH_SIZE_BYTES (8192)
#define BSP_PACKAGE_BGA
#define BSP_PACKAGE_PINS (176)
#endif /* BSP_MCU_DEVICE_PN_CFG_H_ */
```

Start by inspecting bsp_mcu_device_pn_cfg.h and determine which R6M5 device variant and flash-size definition it is intended to represent. Confirm the expected configuration from the project’s device information, then verify that the corrected header is consistent with the repository’s checks; done means the variant reports the intended flash size.

Written by the indexing model from the issue text.