The created rmi device is orphan, which breaks the real device
hierarchy, and can cause some trouble, especially during suspend
and resume sequences. E.g. in case of I2C, rmi dev should be child
of the I2C client device.

Fix this, assigning the transport device as parent of the rmi device.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/1635514971-18415-1-git-send-email-loic.poulain@linaro.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>