media: i2c: s5c73m3: Fix number in auto focus cluster

As of `s5c73m3.h` the auto focus cluster in `s5c73m3_ctrls` has 5 and not 6
controls.

Signed-off-by: Sebastian Gross <sebastian.gross@emlix.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>