serial: 8250_omap: Remove auto-IXON flow control

OMAP h/w-assisted IXON flow control is borked. The transmitter becomes
stuck if XON is never received; clearing the fifos or resetting the
rx flow control bits has no effect.

Remove auto-IXANY as well, since without auto-IXON, it has no purpose.

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