ath9k: fix check for antenna diversity support
ath9k: fix check for antenna diversity support

fixes a regression on single-stream chips introduced in
commit 43c3528430bd29f5e52438cad7cf7c0c62bf4583
"ath9k: implement .get_antenna and .set_antenna"

Signed-off-by: Felix Fietkau <118ed6118e893d16e8c6e0776e0ebc290952c897@openwrt.org>
Reported-by: Marek Lindner <104240d543ffdbcddd3f116d866dc6166bffcd7a@yahoo.de>
Signed-off-by: John W. Linville <2a53bac7a5d324865ef46ec4c38b2c0fba1456b4@tuxdriver.com>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs