ide-tape: remove pipeline-specific code in idetape_space_over_filemarks()

Since we don't do pipeline read-ahead anymore, we don't have to look for
filemarks we have crossed. Therefore, remove the code chunk that does that and
pass on the command to the tape. As a side effect, remove unused
idetape_wait_first_stage().

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