rtw88: import firmware for Realtek's rtw88 supported chipsets.

Import the most recent versions of the firmware images for the
rtw88 driver.

This is based on linux-firmware at 681281e49fb6778831370e5d94e6e1d97f0752d6.

rtw8822c firmware got downgraded in a later commit to 9.9.10:
firmware version 9.9.11 added support for hw_scan and is reportedly
causing more problems than 9.9.10 does.

The license of the firmware matches the previous rtwnfw(4) firmware
files (modulo a Copyright year) and you can find a copy in
sys/contrib/dev/rtw88fw/LICENCE.rtlwifi_firmware.txt.

Add build infrastructure to create the .ko files but do not yet hook
it up to the build until all parts are in the tree.

Approved by: core (imp)
PR: 248235

(cherry picked from commit 73d4ebea3567f18db549638c3d897b6d6758faa4)
(cherry picked from commit 3443476ca9e751cebbb1c467091551bf3d518814)