boot_serial: cbor_encode: Fix encoding data length

static uint32_t get_result_len(const void *const input, uint32_t max_result_len)

{

	uint8_t *u8_result  = (uint8_t *)input;

	size_t i;

	for (; max_result_len > 0; max_result_len--) {

		if (u8_result[max_result_len - 1] != 0) {

	for (i = 0; i < max_result_len; i++) {

#ifdef CONFIG_BIG_ENDIAN

		size_t idx = i;

#else

		size_t idx = max_result_len - 1 - i;

#endif

		if (u8_result[idx] != 0) {

			break;

		}

	}

	max_result_len -= i;

	/* According to specification result length can be encoded on 1, 2, 4

	 * or 8 bytes.

	 */

	cbor_assert(max_result_len <= 8, "Up to 8 bytes can be used to encode length.\n");

	size_t encode_byte_cnt = 1;

	for (size_t i = 0; i <= 3; i++) {

		if (max_result_len <= encode_byte_cnt) {

			max_result_len = encode_byte_cnt;

			break;

		}

		encode_byte_cnt *= 2;

	}

	if ((max_result_len == 1) && (u8_result[0] <= VALUE_IN_HEADER)) {

		max_result_len = 0;

	}