firmware: imx: scu: Fix possible memory leak in imx_scu_probe()

'chan_name' is malloced in imx_scu_probe() and should be freed
before leaving from the error handling cases, otherwise it will
cause memory leak.

Fixes: edbee095 ("firmware: imx: add SCU firmware driver support")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>