On some Qcom SoCs, the Altmode event mode is set to 0xff when
the Type-C port is disconnected.

Handle this specific mode and translate it as the SAFE mode.
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230601-topic-sm8550-upstream-type-c-v5-1-9221cd300903@linaro.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>