ide: inline ide_dma_timeout() into ide_dma_timeout_retry()

Since ide_dma_timeout() is only used by ide_dma_timeout_retry()
inline it there.

There should be no functional changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>