media: stv6110: get rid of a srate dead code

The stv6110 has a weird code that checks if get_property
and set_property ioctls are defined. If they're, it initializes
a "srate" var from properties cache. Otherwise, it sets to
15MBaud, with won't make any sense.

Thankfully, it seems that someone else discovered the issue in
the past, as "srate" is currently not used anywhere!

So, get rid of that really weird dead code logic.

Reported-by: Honza Petrous <jpetrous@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>