Add a null pointer check for wifi_chip in am: 4e634924 am: 26b62570

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2279026



Change-Id: I3a56d4c73b2c3c40dfb650a32cd431f414b4ba7c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>