ARM: dts: qcom: fill secondary compatible for multiple boards

To comply with device-tree definition.

Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210909060343.9665-1-david@ixit.cz