Don't enable local IRQs for PIO-in protocol in driver_cmd_intr().

While at it:

* Remove redundant rq->cmd_type check.

* Read status register after enabling local IRQs for no-data protocol.

v2:
* Re-add DRQ=1 check lost in v1 (noticed by Sergei).
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>