coredump: simplify the implementation of `esp_core_dump_image_erase` function

Closes https://github.com/espressif/esp-idf/pull/6949

components/espcoredump/src/core_dump_flash.c

@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 #include <string.h>
-#include <assert.h>
-#include "esp_core_dump.h"
 #include "esp_partition.h"
 #include "esp_log.h"
 #include "esp_core_dump_types.h"
@@ -438,6 +436,11 @@ esp_err_t esp_core_dump_image_check(void)
 
 esp_err_t esp_core_dump_image_erase(void)
 {
+    /* If flash is encrypted, we can only write blocks of 16 bytes, let's always
+     * write a 16-byte buffer. */
+    uint32_t helper[4] = { BLANK_COREDUMP_SIZE };
+    _Static_assert(sizeof(helper) % 16 == 0, "esp_partition_write() needs multiple of 16 bytes long buffers");
+
     /* Find the partition that could potentially contain a (previous) core dump. */
     const esp_partition_t *core_part = esp_partition_find_first(ESP_PARTITION_TYPE_DATA,
                                                                 ESP_PARTITION_SUBTYPE_DATA_COREDUMP,
@@ -458,21 +461,7 @@ esp_err_t esp_core_dump_image_erase(void)
         return err;
     }
 
-    // helper to create (multiple of) 16 byte long write buffers
-    struct __attribute__((__packed__)) {
-        uint32_t size;
-        char buf[16-sizeof(uint32_t)];
-    } helper;
-
-    _Static_assert(sizeof(helper) % 16 == 0, "esp_partition_write() needs multiple of 16 byte long buffers");
-
-    // Mark core dump as deleted by setting field size
-    helper.size = BLANK_COREDUMP_SIZE;
-
-    // fill the remaining bytes
-    memset(&helper.buf, '\0', sizeof(helper.buf));
-
-    err = esp_partition_write(core_part, 0, &helper, sizeof(helper));
+    err = esp_partition_write(core_part, 0, helper, sizeof(helper));
     if (err != ESP_OK) {
         ESP_LOGE(TAG, "Failed to write core dump partition size (%d)!", err);
     }