drivers: usb: atm: use pr_err() and pr_warn() instead of raw printk()

Since we have the nice helpers pr_err() and pr_warn(), use them instead
of raw printk().

Acked-by: Duncan Sands <duncan.sands@free.fr>
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Link: https://lore.kernel.org/r/20201208093206.24780-3-info@metux.net


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>