[media] omap3isp: stat: update struct ispstat_generic_config's comments

struct ispstat_generic_config's comments refers to isph3a_aewb_config,
isph3a_af_config and isphist_config. But those structs have had their
names prefixed with 'omap3'. So, let's update the comments.

Signed-off-by: David Cohen <david.cohen@nokia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>