ihex: Simplify next record offset calculation

Next record calucaltion can be reduced to a much more tivial ALIGN
operation as follows:

1. Splitting 5 into 2 + 3 we get

   next = ((be16_to_cpu(rec->len) + 2 + 3) & ~3) - 2            (1)

2. Using ALIGN macro we reduce (1) to:

   ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2                      (2)

3. Subsituting 'next' in original next record calucation we get:

   (void *)&rec->data[ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2]  (3)

4. Converting array index to pointer arithmetic we convert (3) into:

   (void *)rec + sizeof(*rec) +
   	 ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2		(4)

5. Subsituting sizeof(*rec) with its value, 6, and substracting 2,
   in (4) we get:

   (void *)rec + ALIGN(be16_to_cpu(rec->len) + 2, 4) + 4        (5)

6. Since ALIGN(X, 4) + 4 == ALIGN(X + 4, 4), (5) can be converted to:

   (void *)rec + ALIGN(be16_to_cpu(rec->len) + 6, 4)            (6)

5. Subsituting 6 in (6) to sizeof(*rec) we get:

   (void *)rec + ALIGN(be16_to_cpu(rec->...