ixgbe: fix unaligned u32 access in ixgbe_update_flash_X550()

ixgbe: fix unaligned u32 access in ixgbe_update_flash_X550()

ixgbe_host_interface_command() treats its buffer as a u32 array. The
local buffer we pass in was a union of byte-sized fields, which gives
it 1-byte alignment on the stack. On strict-align architectures this
can cause unaligned 32-bit accesses.

Add a u32 member to union ixgbe_hic_hdr2 so the object is 4-byte
aligned, and pass the u32 member when calling
ixgbe_host_interface_command().

No functional change on x86; prevents unaligned accesses on
architectures that enforce natural alignment.

Fixes: 49425dfc7451 ("ixgbe: Add support for x550em_a 10G MAC type")
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Jedrzej Jagielski <jedrzej.jagielski@intel.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Fixes: 6a14ee0cfb19 ("ixgbe: Add X550 support function pointers")
Tested-by: Rinitha S <sx.rinitha@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260430-jk-iwl-net-next-2026-04-30-v1-9-6f27ae1cd073@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>