scsi: aacraid: struct {user,}sgmap{,64,raw}: Replace 1-element arrays with flexible...

scsi: aacraid: struct {user,}sgmap{,64,raw}: Replace 1-element arrays with flexible arrays

Replace the deprecated[1] use of 1-element arrays in struct sgmap, struct
sgmap64, struct sgmapraw, struct user_sgmap, and struct user_sgmap64 with
modern flexible arrays. Additionally remove struct user_sgmapraw as it is
unused.

The resulting binary output differences from this change are limited only
to stack space consumption of the smaller "srbu" variable in
aac_issue_safw_bmic_identify() and aac_get_safw_ciss_luns(), as well as the
smaller associated pair of memcpy()s in
aac_send_safw_bmic_cmd(). Artificially growing the size of srbu back to its
prior size removes all binary differences[2].

As an aside, after studying the aacraid driver code I wonder how
aac_send_wellness_command() ever works. It is reporting a size 4 bytes too
small for what it has constructed in memory in the DMA region: sgentry64 is
size 12, whereas sgentry is size 8. Perhaps the hardware doesn't
care. (Regardless, it is unchanged by this patch.)

Link: https://github.com/KSPP/linux/issues/79
Link: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=dev/v6.10-rc2/1-element&id=45e6226bcbc5e982541754eca7ac29f403e82f5e
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20240711215739.208776-2-kees@kernel.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>