intel: fcs: Properly initialize 'timeout' in RNG request before use

commit b86c14665fda1b7044937a7ec76f3f2c63d357ec from
https://github.com/altera-opensource/linux-socfpga.git

 socfpga-5.15.30-lts.

Initialize 'timeout' outside if statement. Otherwise, the initialization
maybe skipped if ret is error. 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>