rpmsg: glink: Rename glink_rpm_xx functions to qcom_glink_xx

Renaming the glink_rpm_xx functions and structs to qcom_glink_xx
equivalents helps to reuse the core glink protocol while adding
support for smem based glink transport in the later patches.
Acked-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>