media: atomisp: change the code to properly wait for sensor

media: atomisp: change the code to properly wait for sensor

The sensor should finish its init before atomisp driver, as
otherwise the atomisp driver won't be able to talk with it.

So, we need to turn atomisp_gmin_platform into a module
again, for it to not depend on atomisp driver to finish
probing, and add some delay at atomisp to let the sensor
driver to finish probing.

Yeah, this is hacky. The real solution here would be to use
the async framework, but for now, our goal is to make the
driver to work. So, let's postpone such change to be done
later.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>