This removes a bunch of duplicated code which does the same as
tty_port_block_til_ready does.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Karsten Keil <isdn@linux-pingi.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>