Make sure to save IRQ states before taking the dma lock, as already done
in it's input_work() counterpart.

Picked up from the upstream dddvb-0.9.33 release.
Signed-off-by: NDaniel Scheller <d.scheller@gmx.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>