Unpack hex string into integers.

    Use little-endian and unsigned int format. Specify number of words to
    unpack with argument words.

def fw_hex_to_int(hex_str, words):
    """Unpack hex string into integers.

    Use little-endian and unsigned int format. Specify number of words to
    unpack with argument words.
    """
    return struct.unpack('<{}H'.format(words), binascii.unhexlify(hex_str))