n_tty: Merge .receive_buf() flavors

N_TTY's direct and flow-controlled flavors of the .receive_buf()
method are nearly identical; fold together.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed