iommu/rockchip: Fix devm_{request,free}_irq parameter

Even though the IOMMU shares IRQ with its master, the struct device
passed to {request,free}_irq is supposed to represent the device that is
signalling the interrupt. This patch makes the driver use IOMMU device
instead of master's device to make things clear.

Signed-off-by: Simon Xue <xxm@rock-chips.com>
Signed-off-by: Shunqian Zheng <zhengsq@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>