[source] ath9k: add a warning to the tx99 config option

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/47540afa5d84dbf019c4227eed758dbc4a4aa01b

commit 47540afa5d84dbf019c4227eed758dbc4a4aa01b
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Thu Feb 2 12:25:01 2017 +0100

    ath9k: add a warning to the tx99 config option
    
    Lots of users try random stuff when they encounter any kind of
    difficulty. I've had to debug a number of cases where people had enabled
    this option for no reason. Hopefully this warning will reduce the number
    of useless support cases.
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 package/kernel/mac80211/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/kernel/mac80211/Makefile b/package/kernel/mac80211/Makefile
index a5e56d9..2451143 100644
--- a/package/kernel/mac80211/Makefile
+++ b/package/kernel/mac80211/Makefile
@@ -248,7 +248,7 @@ define KernelPackage/ath9k/config
 		depends on PACKAGE_kmod-ath9k
 
        config ATH9K_TX99
-               bool "Enable TX99 support"
+               bool "Enable TX99 support (WARNING: testing only, breaks normal operation!)"
                depends on PACKAGE_kmod-ath9k
 
 	config ATH9K_UBNTHSR