drm/msm: Initialize MDSS irq domain at probe time

Since commit 8f59ee9a ("drm/msm/dsi: Adjust probe order"), the
DSI host gets initialized earlier, but this caused unability to probe
the entire stack of components because they all depend on interrupts
coming from the main `mdss` node (mdp5, or dpu1).

To fix this issue, move mdss device initialization (which include irq
domain setup) to msm_mdev_probe() time, as to make sure that the
interrupt controller is available before dsi and/or other components try
to initialize, finally satisfying the dependency.

Fixes: 8f59ee9a

 ("drm/msm/dsi: Adjust probe order")
Co-Developed-By: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20211201202023.2313971-1-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>