i2c: xiic: xiic_xfer(): Fix runtime PM leak on error path

The xiic_xfer() function gets a runtime PM reference when the function is
entered. This reference is released when the function is exited. There is
currently one error path where the function exits directly, which leads to
a leak of the runtime PM reference.

Make sure that this error path also releases the runtime PM reference.

Fixes: fdacc3c7 ("i2c: xiic: Switch from waitqueue to completion")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>