Tools\FitGen: FIX for GCC Build Failure

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2981



Added Type Casting to print UINT64 Value using Printf to fix the GCC build error.

Signed-off-by: cbduggap <chinni.b.duggapu@intel.com>
Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Liu, Zhiguang <zhiguang.liu@intel.com>

Signed-off-by: cbduggap <chinni.b.duggapu@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Zhiguang Liu <zhiguang.liu@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>