Checkpatch reports 'WARNING: printk() should include KERN_<LEVEL>
facility level'. Fix this by specifying a relevant KERN_<LEVEL> value
for each line in which it was missing.

Once they are fixed, checkpatch reports 'WARNING: Prefer [subsystem eg:
netdev]_dbg([subsystem]dev, ... then dev_dbg(dev, ... then
pr_debug(...  to printk(KERN_DEBUG ...'. Fix this by replacing
relevant printk_<level> statements with their netdev_<level>
equivalent.
Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Link: https://lore.kernel.org/r/20200115101208.GA683742@localhost.localdomainSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>