arm64: dts: qcom: msm8916: Drop MSS fallback compatible

MSM8916 was originally using the "qcom,q6v5-pil" compatible for the
MSS remoteproc. Later it was decided to use SoC-specific compatibles
instead, so "qcom,msm8916-mss-pil" is now the preferred compatible.

Commit 60a05ed0 ("arm64: dts: qcom: msm8916: Add MSM8916-specific
compatibles to SCM/MSS") updated the MSM8916 device tree to make use of
the new compatible but still kept the old "qcom,q6v5-pil" as fallback.

This is inconsistent with other SoCs and conflicts with the description
in the binding documentation (which says that only one compatible should
be present). Also, it has no functional advantage since older kernels
could not handle this DT anyway (e.g. "power-domains" in the MSS node is
only supported by kernels that also support "qcom,msm8916-mss-pil").

Make this consistent with other SoCs by using only the
"qcom,msm8916-mss-pil" compatible.

Fixes: 60a05ed0 ("arm64: dts: qcom: msm8916: Add MSM8916-specific compatibles to SCM/MSS")
Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220718140344.1831731-2-stephan.gerhold@kernkonzept.com