staging: vt6655: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break statements instead of just
letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115


Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/863fda60074850bc976974af48fa769c64725e64.1605896059.git.gustavoars@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>