In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a goto statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115Signed-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/cb9b9534572bc476f4fb7b49a73dc8646b780c84.1605896060.git.gustavoars@kernel.orgSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>