Revert "serial/8250: Add support for NI-Serial PXI/PXIe+485 devices"

Revert "serial/8250: Add support for NI-Serial PXI/PXIe+485 devices"

commit 27ed14d0ecb38516b6f3c6fdcd62c25c9454f979 upstream.

This reverts commit fdc2de87124f5183a98ea7eced1f76dbdba22951 ("serial/8250:
Add support for NI-Serial PXI/PXIe+485 devices").

The commit fdc2de87124f ("serial/8250: Add support for NI-Serial
PXI/PXIe+485 devices") introduced a breakage on NI-Serial PXI(e)-RS485
devices, RS-232 variants have no issue. The Linux system can enumerate the
NI-Serial PXI(e)-RS485 devices, but it broke the R/W operation on the
ports.

However, the implementation is working on the NI internal Linux RT kernel
but it does not work in the Linux main tree kernel. This is only affecting
NI products, specifically the RS-485 variants. Reverting the upstream
until a proper implementation that can apply to both NI internal Linux
kernel and Linux mainline kernel is figured out.

Signed-off-by: Je Yen Tam <je.yen.tam@ni.com>
Fixes: fdc2de87124f ("serial/8250: Add support for NI-Serial PXI/PXIe+485 devices")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191127075301.9866-1-je.yen.tam@ni.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>