[media] dib7000m: use pr_foo() instead of printk()

The dprintk() macro relies on continuation lines. This is not
a good practice and will break after commit 56387331
("Merge branch 'printk-cleanups'").

So, instead of directly calling printk(), use pr_foo() macros,
adding a \n leading char on each macro call.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>