serial: core: Fix iotype userspace breakage

serial: core: Fix iotype userspace breakage

commit 2bb785169e9709d41220e5c18b0270883a82f85c upstream.

commit 3ffb1a8193bea ("serial: core: Add big-endian iotype")
re-numbered userspace-dependent values; ioctl(TIOCSSERIAL) can
assign the port iotype (which is expected to match the selected
i/o accessors), so iotype values must not be changed.

Cc: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>