qcom: pmic_glink: enable altmode for SM8450

Create a separate bitmask for sm8550 and enable altmode aux driver
for sm8450 platform to enable pmic-glink altmode events.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230503-topic-sm8450-graphics-dp-next-v3-6-6c43d293995f@linaro.org