drivers/tty: Remove unneeded spaces

coding style fixes in n_tty.c

Signed-off-by: Maximilian Krger <maxfragg@gmail.com>
Signed-off-by: Thorsten Wimann <re06huxa@cip.cs.fau.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>