ath9k: Unlock sc->mutex on error path
ath9k: Unlock sc->mutex on error path

An error path in ath9k_add_interface() did not unlock the sc->mutex and
could leave the driver in quite unresponsive state.

Signed-off-by: Jouni Malinen <b37c2052a78e20d17a47b6db54f61503c44d98ee@atheros.com>
Signed-off-by: John W. Linville <2a53bac7a5d324865ef46ec4c38b2c0fba1456b4@tuxdriver.com>

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