dt-bindings: qcom: document preferred compatible naming

Compatibles can come in two formats.  Either "vendor,ip-soc" or
"vendor,soc-ip".  Qualcomm bindings were mixing both of usages, so add a
DT schema file documenting preferred policy and enforcing it for all new
compatibles, except few existing patterns.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220928152501.490840-1-krzysztof.kozlowski@linaro.org