kernel: add missing config symbol (#19870)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45992 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/generic/config-3.18

@@ -2959,6 +2959,7 @@ CONFIG_PROC_SYSCTL=y
 # CONFIG_R8187SE is not set
 # CONFIG_R8188EU is not set
 # CONFIG_R8712U is not set
+# CONFIG_R8723AU is not set
 # CONFIG_RADIO_ADAPTERS is not set
 # CONFIG_RADIO_AZTECH is not set
 # CONFIG_RADIO_CADET is not set

target/linux/generic/config-4.0

@@ -3005,6 +3005,7 @@ CONFIG_PROC_SYSCTL=y
 # CONFIG_R8187SE is not set
 # CONFIG_R8188EU is not set
 # CONFIG_R8712U is not set
+# CONFIG_R8723AU is not set
 # CONFIG_RADIO_ADAPTERS is not set
 # CONFIG_RADIO_AZTECH is not set
 # CONFIG_RADIO_CADET is not set