ath9k: Fix XLNA bias strength

commit a1783a7b0846fc6414483e6caf646db72023fffd upstream.

The EEPROM parameter to determine whether the bias
strength values for XLNA have to be applied is part
of the miscConfiguration field and not featureEnable.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>