Fix GATT data loss due to segmentation error

Wrong segmentation of HCI ACL data packet makes data loss.
HCI ACL Data packet header(preamble) has to be removed for the calculation.
BR_EDR will have same issue. This fix it also.

This issue came from the following patch.
https://android-review.googlesource.com/c/platform/system/bt/+/1407393

Bug: 201372527
Change-Id: I9d6b813b173512638680bdf301379851a2e34180
Tag: #refactor
Test: compile & verify basic functions working