intel: fcs: release mutex lock in failing path

commit 00295d59 from
git://git.yoctoproject.org/linux-yocto

 v5.10/standard/intel-sdk-5.10/intel-socfpga.

Signed-off-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>