net/ice/base: avoid single-member variable-length structs

net/ice/base: avoid single-member variable-length structs

There are a number of structures that consist of a one-element array as the
only struct member.  Some of those are unused (ice_aqc_add_get_recipe_data,
ice_aqc_get_port_options_data, ice_aqc_dis_txq, etc.) so remove them.
Others are used to index into a buffer/array consisting of a variable
number of a different data or structure type.  Those are unnecessary since
we can use simple pointer arithmetic or index directly into the buffer to
access individual elements of the buffer/array.

Additional code cleanups were done near areas affected by this change.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Qiming Yang <qiming.yang@intel.com>