media: stk1160: Fixed high volume of stk1160_dbg messages

The function stk1160_dbg gets called too many times, which causes
the output to get flooded with messages. Since stk1160_dbg uses
printk, it is now replaced with printk_ratelimited.

Suggested-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Ghanshyam Agrawal <ghanshyam1898@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>