Merge "hidl2aidl: add conversion note to suggest replacing char with int" am: 0f1c3c001a

Original change: https://android-review.googlesource.com/c/platform/system/tools/hidl/+/1550106

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I37ea87403e2951b536c189c5149571c9d84c2feb