media: atomisp: Fix atomisp_try_fmt_cap() always returning YUV420 pixelformat

The atomisp_try_fmt() call in atomisp_try_fmt_cap() replaces
the pixelformat passed by userspace with the sensors native pixelformat.

Which always gets replaced by V4L2_PIX_FMT_YUV420 by atomisp_adjust_fmt()
because raw sensor formats are not supported.

This needs to be fixed so that userspace which does a try_fmt call before
s_fmt does not end up always getting YUV420 even if it passed something
else into the try_fmt call.

To fix this restore the userspace requested pixelformat before
the atomisp_adjust_fmt() call. atomisp_adjust_fmt() will replace this
with V4L2_PIX_FMT_YUV420 in case an unsupported format is requested.

Note this relies on the "media: atomisp: Refactor atomisp_adjust_fmt()"
change, before that atomisp_adjust_fmt() would return -EINVAL for
unsupported pixelformats.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>