Move bufferhubd into system_ext

it is not a part of the system according to
generic_system.mk.

Bug: 173538619
Bug: 167689596
Test: presubmit
Signed-off-by: Roman Kiryanov <rkir@google.com>
Change-Id: If7bbb5d5c19ccec8e510d0a4f1618737e503a794
1 file changed