Input: synaptics-rmi4 - fix error handling in I2C transport driver

Instantiating the rmi4 I2C transport driver without interrupts assigned
(for example using manual i2c instantiation from the command line)
caused the driver to fail to load, but it does not clean up its regulator
or transport device registrations. Result is a crash at a later time,
for example when rebooting the system.

Fixes: 946c8432 ("Input: synaptics-rmi4 - support regulator supplies")
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>