USB: wusbcore: add in missing white space in error message text

A dev_err message spans two lines and the literal string is missing
a white space between words. Add the white space and reformat the
message to not span multiple lines.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>