[media] cx231xx: Cleanup printk at the driver

There are lots of debug printks printed with pr_info. Also, the
printk's data are not too coherent:

- there are duplicated driver name at the print format;
- function name format string differs from function to function;
- long strings broken into multiple lines;
- some printks just produce ugly reports, being almost useless
  as-is.

Do a cleanup on that.

Still, there are much to be done in order to do a better printk
job on this driver, but, at least it will now be a way less
verbose, if debug printks are disabled, and some logs might
actually be useful.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>