Fix floss build breakage "bt_transport.h" not found

The include statement was added by https://r.android.com/3343104 but
not being changed by https://r.android.com/3344385.

Bug: 369703686
Test: mmm packages/modules/Bluetooth
Test: ./build-in-container.py
Test: USE=floss_upstream emerge-brya floss
Flag: EXEMPT, no logical change
Change-Id: I8e37861cb2bbc85a8598e242c58f21c08a8637d4