Build only for current architecture by default

From now on, libbluetooth.so, and all unit tests will be compiled for
the current device platform only.

libbluetooth-types is an exception from rule, as some vendor libraries
are still compiled for 32bit.

Bug: 68028239
Test: compile and run Bluetooth
Change-Id: I51bb4da2a9e1e4e9a03c43f2825bd1dbd4a5ca58