rpmsg: char: Export alias for RPMSG ID rpmsg-raw from table

rpmsg: char: Export alias for RPMSG ID rpmsg-raw from table

Module aliases are used by userspace to identify the correct module to
load for a detected hardware. The currently supported RPMSG device IDs for
this module include "rpmsg-raw", but the module alias is "rpmsg_chrdev".

Use the helper macro MODULE_DEVICE_TABLE(rpmsg) to export the correct
supported IDs. And while here, to keep backwards compatibility we also add
the other ID "rpmsg_chrdev" so that it is also still exported as an alias.

This has the side benefit of adding support for some legacy firmware
which still uses the original "rpmsg_chrdev" ID. This was the ID used for
this driver before it was upstreamed (as reflected by the module alias).

Signed-off-by: Andrew Davis <afd@ti.com>
Acked-by: Hari Nagalla <hnagalla@ti.com>
Tested-by: Hari Nagalla <hnagalla@ti.com>
Link: https://lore.kernel.org/r/20250619205722.133827-1-afd@ti.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>