msm8960-common: fix up tethering

Without this tethering fails on T-Mobile and Sprint. Not needed until
http://review.cyanogenmod.org/#/c/55035/5 was merged.

Change-Id: I07e3b86bffa8d4ffa45a4908380d6c7e0f5bfe06
Merge branch 'cm-11.0' of github.com:CyanogenMod/android_device_samsung_msm8960-common into cm-11.0