staging: rtl8188eu: Add device code for TP-Link TL-WN727N v5.21

This device was added to the stand-alone driver on github.
Add it to the staging driver as well.

Link: https://github.com/lwfinger/rtl8188eu/commit/b9b537aa25a8
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191228143725.24455-1-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>