i2c: cadence: Unregister the clk notifier in error path

This patch ensures that the clock notifier is unregistered
when driver probe is returning error.

Fixes: df8eb569

 ("i2c: Add driver for Cadence I2C controller")
Signed-off-by: Satish Nagireddy <satish.nagireddy@getcruise.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>