rpmsg: glink: Switch to SPDX license identifier

Use the appropriate SPDX license identifier in various rpmsg
glink driver source files and drop the previous boilerplate
license text.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
5 files changed