rpmsg: glink: spi: Rename structs

Rename structs that have the same identifier as native glink. This will
help debugging glink from ramdumps and prevent collisions in the
debugger. Fix alignment issues caused from name changes.

Change-Id: I922133e45681bdbefba7b5e81a6ab3da9dd1ddc0
Signed-off-by: Chris Lew <clew@codeaurora.org>