drm/msm/dpu: remove irq_idx argument from IRQ callbacks

There is no point in passing the IRQ index to IRQ callbacks, no function
uses that. Drop it at last.

Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/550925/
Link: https://lore.kernel.org/r/20230802100426.4184892-3-dmitry.baryshkov@linaro.org