ide-tape: remove struct idetape_parameter_block_descriptor_t

Also, shorten function name idetape_get_blocksize_from_block_descriptor() and
move its definition up thereby getting rid of its forward declaration.

Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>