qd65xx: remove pointless qd_{read,write}_reg() (take 2)

These functions are atomic so locking is pointless (noticed by Sergei).

v2:
We can now just use local_irq_save/restore() in qd_testreg() (noticed by Jeff).

Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>