i2c: xiic: Make sure to disable clock on .remove()

If for whatever reasons pm_runtime_resume_and_get() failed, .remove() is
exited early, the clock isn't freed and runtime PM state isn't reset.

The right thing to do however is to free all resources that don't need
HW access after a problem with runtime PM. Also issue a warning in that
case and return 0 to suppress a less helpful warning by the driver core.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>