serial: Remove RM9000 series serial driver.

Now that support for RM9000 and platforms based on it has been removed,
remove the serial driver for it as well.  It's really only been a quirk
for an almost 8250 compatible UART anyway.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
 drivers/tty/serial/8250/8250.c  | 70 +----------------------------------------
 drivers/tty/serial/8250/Kconfig |  9 ------
 include/linux/serial_core.h     |  1 -
 3 files changed, 1 insertion(+), 79 deletions(-)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>