intel: fcs: Copy data from user space to kernel space via copy_from_user

commit a91a5ba243c79d2c52cf3ca85fcfcd5d099fe718 from
https://github.com/altera-opensource/linux-socfpga.git

 socfpga-5.15.30-lts.

Properly copy the data from user space to kernel space via copy_from_user
API. This issue is detected by Klocwork.

Signed-off-by: Siew Chin Lim <elly.siew.chin.lim@intel.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>