media: staging: ipu3-imgu: Set fields before media_entity_pads_init()

[ Upstream commit 87318b7092670d4086bfec115a0280a60c51c2dd ]

The imgu driver fails to probe with the following message because it
does not set the pad's flags before calling media_entity_pads_init().

[   14.596315] ipu3-imgu 0000:00:05.0: failed initialize subdev media entity (-22)
[   14.596322] ipu3-imgu 0000:00:05.0: failed to register subdev0 ret (-22)
[   14.596327] ipu3-imgu 0000:00:05.0: failed to register pipes (-22)
[   14.596331] ipu3-imgu 0000:00:05.0: failed to create V4L2 devices (-22)

Fix the initialization order so that the driver probe succeeds. The ops
initialization is also moved together for readability.

Fixes: a0ca1627 ("media: staging/intel-ipu3: Add v4l2 driver based on media framework")
Cc: <stable@vger.kernel.org> # 6.7
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Hidenori Kobayashi <hidenorik@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>