firmware: qcom_scm: Add compatible for MSM8976 SoC

Add compatible for SCM on MSM8976.

Signed-off-by: Adam Skladowski <a39.skl@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220307191726.10869-5-a39.skl@gmail.com