Remove unused stack/l2cap::partial_segment_being_sent am: 9dda5faf am:...

Remove unused stack/l2cap::partial_segment_being_sent am: 9dda5faf am: 1c421888 am: cd00ab1c am: 940ef1d2

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Bluetooth/+/2084124



Change-Id: Ib6c0f2f993044f891c6f22de6412795e50706420
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>