drivers/tty/serial/crisv10.c: remove dead #ifdef blocks

ETRAX_RS485_{ON_PORT_G, LTC1387} are not defined in Kconfig.  The
affected #ifdef block have not been compiled for years, so remove them
entirely.

Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>