wifi: qtnfmac: Avoid multiple -Wflex-array-member-not-at-end warnings

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

So, in order to avoid ending up with a flexible-array member in the
middle of other structs, we use the `__struct_group()` helper to
create a new tagged `struct qlink_tlv_hdr_fixed`. This structure
groups together all the members of the flexible `struct qlink_tlv_hdr`
except the flexible array.

As a result, the array is effectively separated from the rest of the
members without modifying the memory layout of the flexible structure.
We then change the type of the middle struct member currently causing
trouble from `struct qlink_tlv_hdr` to `struct qlink_tlv_hdr_fixed`.

We also want to ensure that when new members need to be added to the
flexible structure, they are always included within the newly created
tagged struct. For this, we use `static_assert()`. This ensures that
the memory layout for both the flexible structure and the new tagged
struct is the same after any changes.

This approach avoids having to implement `struct qlink_tlv_hdr_fixed`
as a completely separate structure, thus preventing having to maintain
two independent but basically identical structures, closing the door
to potential bugs in the future.

So, with this changes, fix 66 of the following warnings:
drivers/net/wireless/quantenna/qtnfmac/qlink.h:1681:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/wireless/quantenna/qtnfmac/qlink.h:1660:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/wireless/quantenna/qtnfmac/qlink.h:1646:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/wireless/quantenna/qtnfmac/qlink.h:1621:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/wireless/quantenna/qtnfmac/qlink.h:1609:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/net/wireless/quantenna/qtnfmac/qlink.h:1570:30: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://patch.msgid.link/Z6K0Nd_IprrhS6pn@kspp
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

0 files changed, 0 insertions, 0 deletions