fpga: dfl: fix typo in header file

fix typo "definitons" ==> "definitions" in DFHv1 Register Offset comment.

Signed-off-by: Mukesh Kumar Sisodiya <mukeshkumarsisodiya1981@gmail.com>
Link: https://lore.kernel.org/r/20251226150408.2802-1-mukeshkumarsisodiya1981@gmail.com
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>