Include product/generic.mk instead of 64bitonly/product/vendor.mk am: 1bd715bcdf

Original change: https://android-review.googlesource.com/c/device/generic/car/+/2927724

Change-Id: I70d98342ee8f0e3ed7567a24f96d77d1b8ccf71f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>