dt-bindings: soc: qcom: Support GLINK intents

Virtual GLINK channels may know what throughput to expect from a
remoteproc. An intent advertises to the remoteproc this channel is
ready to receive data. Allow a channel to define the size and amount of
intents to be prequeued.

Change-Id: I815dc1ccef4f31c4d274e717db17dbb6fb3e4e39
Signed-off-by: Chris Lew <clew@codeaurora.org>