BACKPORT: rpmsg: virtio: Fix possible double free in rpmsg_probe()

[ Upstream commit c2eecefe ]

vch will be free in virtio_rpmsg_release_device() when
rpmsg_ns_register_device() fails. There is no need to call kfree() again.

Fix this by changing error path from free_vch to free_ctrldev.

Bug: 238480163
Fixes: c486682a ("rpmsg: virtio: Register the rpmsg_char device")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Tested-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20220426060536.15594-2-hbh25y@gmail.com


Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Iaf926a7a3bfe026102c9763f7aef7e74aaaa0e24