staging: ION: remove some references to CONFIG_ION

staging: ION: remove some references to CONFIG_ION

With commit 5e34069868a1 ("staging: ion: remove from the tree"), ION and
its corresponding config CONFIG_ION is gone. Remove stale references
from drivers/staging/media/atomisp/pci and from the recommended Android
kernel config.

Fixes: 5e34069868a1 ("staging: ion: remove from the tree")
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Rob Herring <robh@kernel.org>
Cc: linux-media@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Signed-off-by: Matthias Maennich <maennich@google.com>
Link: https://lore.kernel.org/r/20210106155201.2845319-1-maennich@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>