M2354: Remove flash_read override originally for test chip

In test chip, byte-read (LDRB) last byte of flash in non-secure world always gets 0xFF.
This is got around by overriding flash_read(...). Now, the override can remove in MP chip.

Author: ccli8

targets/TARGET_NUVOTON/TARGET_M2354/flash_api.c

@@ -117,18 +117,4 @@ void flash_set_target_config(flash_t *obj)
 
 #endif  // #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
 
-int32_t flash_read(flash_t *obj, uint32_t address, uint8_t *data, uint32_t size)
-{
-    memcpy(data, (const void *)address, size);
-    /* In test chip, byte-read (LDRB) last byte of flash in non-secure world
-     * always gets 0xFF. Get around it.
-     *
-     * Remove the flash_read(...) override in MP chip. */
-    if (size && (address + size) == 0x10100000) {
-        volatile uint32_t *last_word = (volatile uint32_t *) 0x100FFFFC;
-        data[size - 1] = (uint8_t) ((*last_word & 0xFF000000) >> 24);
-    }
-    return 0;
-}
-
 #endif  // #if DEVICE_FLASH