Merge branch 'qualcomm-bam-dmux'

Stephan Gerhold says:

====================
net: wwan: Add Qualcomm BAM-DMUX WWAN network driver

The BAM Data Multiplexer provides access to the network data channels
of modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916
or MSM8974. This series adds a driver that allows using it.

All the changes in this patch series are based on a quite complicated
driver from Qualcomm [1]. The driver has been used in postmarketOS [2]
on various smartphones/tablets based on Qualcomm MSM8916 and MSM8974
for more than a year now with no reported problems. It works out of
the box with open-source WWAN userspace such as ModemManager.

[1]: https://source.codeaurora.org/quic/la/kernel/msm-3.10/tree/drivers/soc/qcom/bam_dmux.c?h=LA.BR.1.2.9.1-02310-8x16.0
[2]: https://postmarketos.org/

Changes in v3:
  - Clarify DT schema based on discussion
  - Drop bam_dma/dmaengine patches since they already landed in 5.16
  - Rebase on net-next
  - Simplify cover letter and commit messages

Changes in v2:
  - Rename "qcom,remote-power-collapse" -> "qcom,powered-remotely"
  - Rebase on net-next and fix conflicts
  - Rename network interfaces from "rmnet%d" -> "wwan%d"
  - Fix wrong file name in MAINTAINERS entry
====================

Signed-off-by: David S. Miller <davem@davemloft.net>