Only one top-level devicetree node can be defined per file; move
qcom,mem-buf-msgq to its own.
Fixes:
../Documentation/devicetree/bindings/soc/qcom/qcom,mem-buf.yaml:56:1:
[error] duplication of key "properties" in mapping (key-duplicates).
Change-Id: I8f7b5bdd94afa38ade3b2173ee2d99c6906cc74d
Signed-off-by: Patrick Daly <quic_pdaly@quicinc.com>