iwlegacy: add missing null check
iwlegacy: add missing null check

lq_sta has other null checks in this function.
assuming they are correct, this additional null check
should be added too.

Incorporating suggestion from Gustavo Padovan.

Signed-off-by: Greg Dietsche <fab22ba70c1d97aa0b34ba823fba551a1691c0ec@cuw.edu>
Signed-off-by: John W. Linville <2a53bac7a5d324865ef46ec4c38b2c0fba1456b4@tuxdriver.com>

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