Impact: remove unnecessary code path
Block pc requests always use bio and rq->data is always NULL.  No need
to worry about !rq->bio cases in idefloppy_block_pc_cmd().  Note that
ide-atapi uses ide_pio_bytes() for bio PIO transfer which handle sg
fine.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
        ide_init_pc(pc);
        memcpy(pc->c, rq->cmd, sizeof(pc->c));
        pc->rq = rq;
-       if (rq->data_len && rq_data_dir(rq) == WRITE)
-               pc->flags |= PC_FLAG_WRITING;
-       pc->buf = rq->data;
-       if (rq->bio)
+       if (rq->data_len) {
                pc->flags |= PC_FLAG_DMA_OK;
-       /*
-        * possibly problematic, doesn't look like ide-floppy correctly
-        * handled scattered requests if dma fails...
-        */
+               if (rq_data_dir(rq) == WRITE)
+                       pc->flags |= PC_FLAG_WRITING;
+       }
+       /* pio will be performed by ide_pio_bytes() which handles sg fine */
+       pc->buf = NULL;
        pc->req_xfer = pc->buf_size = rq->data_len;
 }