bus: mhi: host: pci_generic: Revert "Add a secondary AT port to Telit FN990"

This reverts commit 2d5253a0.
There are 2 commits with commit message "Add a secondary AT port to Telit
FN990":

commit 2d5253a0 ("bus: mhi: host: pci_generic: Add a secondary AT port
to Telit FN990")
commit 479aa3b0 ("bus: mhi: host: pci_generic: Add a secondary AT port
to Telit FN990")

This turned out to be due to the patch getting applied through different
trees and git settled on a resolution while applying it second time. But
the second AT port of Foxconn devices don't work in PCIe mode. So the
second commit needs to be reverted.

Cc: stable@vger.kernel.org # 6.2
Fixes: 2d5253a0

 ("bus: mhi: host: pci_generic: Add a secondary AT port to Telit FN990")
Signed-off-by: Slark Xiao <slark_xiao@163.com>
Reviewed-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/20230310101715.69209-1-slark_xiao@163.com
[mani: massaged the commit message a bit, added fixes tag and CCed stable]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>