Incorporate suggestions for tty core debug macro improvements
 - printk(KERN_DEBUG) => pr_debug()
 - ##args => ##__VA_ARGS__
 - remove do {} while()
 - output tty_name() first

cc: Joe Perches <joe@perches.com>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>