clat: split read_packet in twain am: e6e0c009b9 am: dadeab06b6

Original change: https://android-review.googlesource.com/c/platform/external/android-clat/+/2394652

Change-Id: Ib78bec8a185cb1e30cf092ce2ddcfe6caf45b265
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>