Add support for the other MaxLinear/Exar UARTs

The current version of the xr_serial driver handles one one of the several MaxLinear/Exar UARTs and UART bridges. There are currently 12 such models. Only one is currently supported.

They were tested only on XR21B1410 and XR21B1424 models, although I'm pretty much confident that the other models will also work, as they're very close to either one of those.

Patch 1 is just a cleanup for the registers namespace. It removes the model number from registers that are used on multiple versions of the chipset.

Patch 2 adds a table to be used to map the register for each specific variant of this chipset;

Patch 3 adds support for XR21B1412 and XR21B1414. The only difference on those devices is that they support multiple UART ports.

Patch 4 adds support for XR21B142X, which uses a mix of data and control interfaces to setup the line discipline.

Patch 5 adds support for XR21B1410 variant. This one is identical to XR21B1411, except that it uses a different register set;

Patch 6 adds support for XR2280X devices:
https://www.maxlinear.com/product/interface/bridges/usb-ethernet-bridges/xr22800

Such devices are compound devices that are similar to the USB UARTs from programming PoV. The only difference is the register set.

Patch 7 updates the CDC ignore list.

After this series, all MaxLinear USB UARTs described at:
https://www.maxlinear.com/products/interface/uarts/usb-uarts

Should be supported, except for XR21B1421. This one have just a control interface, and uses standard HID protocol. No idea how to support it. Also, I don't have such device to test ;-)

In order to write this patch series, I used the datasheets, plus the Linux driver source code, available at MaxLinear, and a previous port made by Patong Yang:

https://lore.kernel.org/linux-usb/20180404070634.nhspvmxcjwfgjkcv@advantechmxl-desktop

---
v2:
- rebased on the top of next-20210323;
- free port_priv before calling usb_set_serial_data.

Mauro Carvalho Chehab (7):
USB: serial: xr: simplify its namespace
USB: serial: xr: use a table for device-specific settings
USB: serial: xr: add support for multi-port XR21V141X variants
USB: serial: xr: add support for XR21B142X devices
USB: serial: xr: add support for XR21B1411
USB: serial: xr: add support for XR2280X devices
USB: cdc-acm: add other non-standard xr_serial models to ignore list

 drivers/usb/class/cdc-acm.c    |  17 +-
 drivers/usb/serial/xr_serial.c | 694 +++++++++++++++++++++++++--------
 2 files changed, 556 insertions(+), 155 deletions(-)

2.30.2