ice: fix access-beyond-end in the switch code

Global `-Warray-bounds` enablement revealed some problems, one of
which is the way we define and use AQC rules messages.
In fact, they have a shared header, followed by the actual message,
which can be of one of several different formats. So it is
straightforward enough to define that header as a separate struct
and then embed it into message structures as needed, but currently
all the formats reside in one union coupled with the header. Then,
the code allocates only the memory needed for a particular message
format, leaving the union potentially incomplete.
There are no actual reads or writes beyond the end of an allocated
chunk, but at the same time, the whole implementation is fragile and
backed by an equilibrium rather than strong type and memory checks.

Define the structures the other way around: one for the common
header and the rest for the actual formats with the header embedded.
There are no places where several union members would be used at the
same time anyway. This allows to use proper struct_size() and let
the compiler know what is going to be done.
Finally, unsilence `-Warray-bounds` back for ice_switch.c.

Other little things worth mentioning:
* &ice_sw_rule_vsi_list_query is not used anywhere, remove it. It's
  weird anyway to talk to hardware with purely kernel types
  (bitmaps);
* expand the ICE_SW_RULE_*_SIZE() macros to pass a structure
  variable name to struct_size() to let it do strict typechecking;
* rename ice_sw_rule_lkup_rx_tx::hdr to ::hdr_data to keep ::hdr
  for the header structure to have the same name for it constistenly
  everywhere;
* drop the duplicate of %ICE_SW_RULE_RX_TX_NO_HDR_SIZE residing in
  ice_switch.h.

Fixes: 9daf8208 ("ice: Add support for switch filter programming")
Fixes: 66486d89 ("ice: replace single-element array used for C struct hack")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Marcin Szycik <marcin.szycik@linux.intel.com>
Acked-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://lore.kernel.org/r/20220601105924.2841410-1-alexandr.lobakin@intel.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>