media: staging: rkisp1 stats: set a measure flag with '|=' instead of '='

The flag RKISP1_CIF_ISP_STAT_AFM_FIN that indicates a type of
statistics is mistakenly set with '=' instead of '|='
this might set off previous flags.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>