dt-bindings: soc: qcom: Extend GLINK to cover SMEM

In addition to using GLINK for communication with the RPM it can be
used ontop of SMEM for communicating with remoteprocs, extend the
binding to also describe this case and reference the GLINK binding from
the affected remoteproc bindings.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>