V4L/DVB (7748): tuner-core: some adjustments at tuner logs, if debug enabled

set_addr log were almost useless: discarded SET_TYPE_ADDR commands weren't
reported.

This patch changed set_addr printk to print a message only if set_addr is
wrong.

It also fix printk at set_type, since, if an attach were failing, nothing
were reported.

With the current code, working or not, a call to set_addr will produce a debug
printk.

also, set_type() were producing a false error message on tuner_xc2028, since
it were requesting for setting a frequency on a place where firmware name
weren't set yet.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>