We are planning to support more chipsets, e.g. 8852C. Before that, we
consider architecutre to handle multiple kinds of chipsets. Obviosuly,
based on original design, rtw89_core module will have large size even
if there is only one chipset under running. It is because all chipset
related things are put in rtw89_core now. To reduce such overhead, we
extract modules of rtw89 and adjust dependencies between modules.

The following assumes that 8852AE, 8852AU, and 8852CE are all supported,
we describe the difference before and after extraction.

[Before extraction]
                                             -------------
       |------------------------------------ | rtw89_usb |
       V                                     -------------
---------------------------------------      -------------
| rtw89_core (including 8852A, 8852C) | <--- | rtw89_pci |
---------------------------------------      -------------
The data of 8852A and 8852C are built in rtw89_core.
And rtw89_pci is the entry of 8852AE and 8852CE.
And rtw89_usb is the entry of 8852AU.

[After extraction]
                    -------------           ----------------
       |----------- | rtw89_usb | <-------- | rtw89_8852au |
       |            -------------           ----------------
       V            ---------------                |
--------------      |             | <---------------
| rtw89_core | <--- | rtw89_8852a |
--------------      |             | <---------------
   ^   ^            ---------------                |
   |   |            -------------           ----------------
   |   |            |           | <-------- | rtw89_8852ae |
   |   |----------- | rtw89_pci |           ----------------
   |                |           | <-----------------
   |                -------------                  |
   |                ---------------         ----------------
   |--------------- | rtw89_8852c | <------ | rtw89_8852ce |
                    ---------------         ----------------
The data of 8852A/8852C is extracted to rtw89_8852a/rtw89_8852c.
And rtw89_pci/rtw89_usb handles only common flow of pci/usb bus.
Finally, 8852AE, 8852AU, and 8852CE have individual entry modules,
i.e. rtw89_8852ae, rtw89_8852au, and rtw89_8852ce correspondingly.
Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211221025828.25092-1-pkshih@realtek.com