[PATCH] ide: fix null request pointer for taskfile ioctl

When doing ioctl HDIO_DRIVE_TASKFILE, the ide_task_t's request pointer is
never set, but flagged_taskfile and do_rw_taskfile pass it as a parameter
to the prehandler.  The kernel will oops taskfile pio-out commands because
of this (taskfile pio-in doesn't use a prehandler).  This fix sets the
request pointer at the time the request is created to stop this oops.

Signed-off-by: Timothy Thelin <timothy.thelin@wdc.com>
Cc: "Bartlomiej Zolnierkiewicz" <bzolnier@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>