...between "error: unannotated fall-through between switch labels
[-Werror,-Wimplicit-fallthrough]" (in some builds, for the original code) and
"error: fallthrough annotation in unreachable code
[-Werror,-Wimplicit-fallthrough]" (in other builds, after adding
SAL_FALLTHROUGH).

Change-Id: I75bbefd69c81f43f22117f8ad110237de24e18af