Add a null pointer check for wifi_chip in am: 4e634924 am: 26b62570 am: 590248f6

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



Change-Id: Icc25a1b51aaf570a197b2326d562d5388f4dd938
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>