[media] mt9v032: Correct the logic for the auto-exposure setting

The driver uses the ctrl value passed in as a bool to determine whether
to enable auto-exposure, but the auto-exposure setting is defined as an
enum where AUTO has a value of 0 and MANUAL has a value of 1. This leads
to a reversed logic where if you send in AUTO, it actually sets manual
exposure and vice-versa.

Signed-off-by: Kartik Mohta <kartikmohta@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>