media: i2c: imx290: set the format before VIDIOC_SUBDEV_G_FMT is called

Commit d46cfdc8

 upstream.

With the current driver 'media-ctl -p' issued right after the imx290 driver
is loaded prints:
pad0: Source
             [fmt:unknown/0x0]

The format value of zero is due to the current_format field of the imx290
struct not being initialized yet.

As imx290_entity_init_cfg() calls imx290_set_fmt(), the current_mode field
is also initialized, so the line which set current_mode to a default value
in driver's probe() function is no longer needed.

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>