rtlwifi/rtl8712u Revert firmware

Although the newest firmware for the RTL8192SU, which is found in vendor
driver rtl8188C_8192C_8192D_usb_linux_v3.4.2_3727.20120404, works with most
devices, it causes drops of the wireless connection for the ASUS WL-167G V3
(USB ID 0b05:1791), the D-Link DWA131 (07d1:3303), and probably others.
Tests show that the firmware from vendor driver
rtl8712_8188_8191_8192SU_usb_linux_v7_0.20100831 works better.

This commerts reverts to that older firmware.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

WHENCE

@@ -1751,7 +1751,8 @@ Licence:
 Driver: r8712u - Realtek 802.11n WLAN driver for RTL8712U
 
 File: rtlwifi/rtl8712u.bin
-Info: From Vendor's rtl8188C_8192C_8192D_usb_linux_v3.4.2_3727.20120404
+Info: From Vendor's rtl8712_8188_8191_8192SU_usb_linux_v7_0.20100831
+      Reverted rtl8188C_8192C_8192D_usb_linux_v3.4.2_3727.20120404
 
 Licence: Redistributable. See LICENCE.rtlwifi_firmware.txt for details.