media: atomisp: atomisp_v4l2: Removed unnecessary code

Here is the last step of #ifdef ISP2401 removal work. Since the driver
became generic, this part of the code was no longer needed and can
be removed.

Link: https://lore.kernel.org/r/20230802095606.1298152-13-hpa@redhat.com



Signed-off-by: Kate Hsuan <hpa@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>