ANDROID: GKI: defconfig: enable BTF debug info

Build BTF type info into the kernel to enable use of BPF-based tools
such as BCC's libbpf-tools.

Bug: 203823368
Test: build
Signed-off-by: Connor O'Brien <connoro@google.com>
Change-Id: Ice20d6bbf83b3a2407a553a37a9befff6c6bb66d