rtw88: update firmware information and README

The rtw88/README should claim support for RTL8723DE devices, add them.

And also there will have confusion that the 802.11ac driver rtw88
supports an 802.11n device RTL8723DE, add the information to WHENCE.

To prevent some fo the distros not including WOW firmware but have WOW
support and cannot load firmware at the end, add a note for it.
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

WHENCE

@@ -2872,6 +2872,14 @@ File: rtw88/rtw8723d_fw.bin
 
 Licence: Redistributable. See LICENCE.rtlwifi_firmware.txt for details.
 
+    These firmware should be put under /lib/firmware/rtw88/
+    And note that the rtw88 driver is able to support wake-on-wireless LAN
+    for RTL8822C devices, after kernel v5.6+. So, make sure the firmware
+    rtw88/rtw8822c_wow_fw.bin is also packed, otherwise the firmware load
+    fail could be a problem.
+    Although RTL8723D devices are 802.11n device, they are also supported
+    by rtw88 because the hardware arch is similar.
+
 --------------------------------------------------------------------------
 
 Driver: rtl8192ee - Realtek 802.11n WLAN driver for RTL8192EE

rtw88/README

@@ -26,3 +26,6 @@ RTL8822CE
     rtw8822c_fw.bin
     rtw8822c_wow_fw.bin
 
+RTL8723DE
+    rtw8723d_fw.bin
+