Message logged by 'dev_xxx()' or 'pr_xxx()' should end with a '\n'.

Fixes: 48ba02b2 ("usb: gadget: add udc driver for max3420")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Felipe Balbi <balbi@kernel.org>