hsi: fix double kfree

When device_register() fails, kfree() is called in hsi_client_release(),
hence there is no need to call kfree in err3 again.

Fixes: a2aa2473 ("HSI: Add common DT binding for HSI client devices")
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>