Add WWAN framework and drivers support

[Chris Chiu]

[SRU Justification]

[Impact]
The Quectel SDX24 EM160R-GL 4G LTE CAT16 PCIE Modem and Foxconn SDX55 T99W175 5G sub6 PCIE Modem are not supported in 5.11 kernel yet. The new WWAN framework and driver support are required to be backported to detect and control the new WWAN modules.

[Fix]
Backport the WWAN framework and drivers support from mainline kernel 5.13.

[Test Case]
Verify whether the Quectel/Foxconn WWAN module are detected or not. And use either `mmcli` commands or NetworkSettings Panel to test the connection.

[Where problem could occur]
Since the WWAN framework is totally new which makes use of the existing MHI bus drivers and protocols, it should be compatible with old WWAN modules. The regression can be considered as low.

[Chris Chiu (mschiu77)]

https://git.launchpad.net/~mschiu77/ubuntu/+source/linux-intel/log/?h=austin-1928665 is create for pull request review.

[You-Sheng Yang (vicamo)]

Two fixing commits missed:
  * 0b67808ade88 bus: mhi: pci_generic: Fix possible use-after-free in mhi_pci_remove()
  * c7711c22c6eb bus: mhi: pci_generic: T99W175: update channel name from AT to DUN

$ ~/bin/find-fixes.sh HEAD~73..HEAD^ korg/master
###### Checking commit 7b952ef3d7ef ("net: Add a WWAN subsystem") ######
  * Checking for origin 9a44c1cc6388 ...
      fixes found in korg/master:57e222475545 b8c55ce266de
        (applied) 57e222475545 net: wwan: core: Return poll error in case of port removal
        (applied) b8c55ce266de net: wwan: Fix bit ops double shift
###### Checking commit a4616f133318 ("net: Add Qcom WWAN control driver") ######
  * Checking for origin fa588eba632d ...
      fixes found in korg/master:a926c025d56b
        (applied) a926c025d56b net: wwan: mhi_wwan_ctrl: Fix RX buffer starvation
###### Checking commit 30043e766676 ("mhi: pci_generic: Add health-check") ######
  * Checking for origin 8562d4fe34a3 ...
      fixes found in korg/master:0b67808ade88
                  0b67808ade88 bus: mhi: pci_generic: Fix possible use-after-free in mhi_pci_remove()
###### Checking commit d103a5b5ec37 ("mhi: core: Factorize mhi queuing") ######
  * Checking for origin a8f75cb348fd ...
      fixes found in korg/master:0ecc1c70dcd3
        (applied) 0ecc1c70dcd3 bus: mhi: core: Fix invalid error returning in mhi_queue
###### Checking commit 8bf83f071164 ("bus: mhi: pci_generic: Introduce Foxconn T99W175 support") ######
  * Checking for origin aac426562f56 ...
      fixes found in korg/master:c7711c22c6eb
                  c7711c22c6eb bus: mhi: pci_generic: T99W175: update channel name from AT to DUN

[You-Sheng Yang (vicamo)]

SRU: https://lists.ubuntu.com/archives/kernel-team/2021-June/121638.html

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!