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

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

This reverts commit c1acea938675891c4bd006bd8b548d799a8817d5 ("serial/8250:
Add support for NI-Serial PXI/PXIe+485 devices").

The commit c1acea938675 ("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: c1acea938675 ("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>