net/ice/base: use struct size helper

net/ice/base: use struct size helper

For structures using the common C "struct hack" technique to create a
flexible length structure member at the end of the structure, use the
ice_struct_size macro to determine the length of the structure instead
of open coding the calculation.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Qiming Yang <qiming.yang@intel.com>