pata_bk3710: clear status bits of BMISP on chipset initialization

Clear IORDYINT, INTRSTAT and DMAERROR bits of BMISP register
(value '1' needs to be written to the bit to clear it).

Suggested-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>