gs201: Bypass BTS if it's unsupported

Fix CSI failed to enable due to BTS. Interact with BTS only if lwis
devices successfully registered BTS when probing.

Bug: 189227685
Change-Id: If26955824d554b5119ba1f62c1982e6443aa725d
Signed-off-by: Tzu-Yang Chiu <flarechiu@google.com>