The rpmsg_chrdev driver has been replaced by the rpmsg_ctrl driver
for the /dev/rpmsg_ctrlX devices management. The reference for the
driver override is now the rpmsg_ctrl.

Update the rpmsg_chrdev_register_device function to reflect the update,
and rename the function to use the rpmsg_ctrldev prefix.

The platform drivers are updated accordingly.
Signed-off-by: NArnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Reviewed-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220124102524.295783-8-arnaud.pouliquen@foss.st.com