Add a null pointer check for wifi_chip in am: 4e6349240e am: 26b625704e am: 590248f68e

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>