There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Replace a one-element array with a flexible-array member in struct
imgu_fw_header and use the struct_size() helper.

This also helps with the ongoing efforts to globally enable
-Warray-bounds and get us closer to being able to tighten the
FORTIFY_SOURCE routines on memcpy().

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/79
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/staging/media/ipu3/ipu3-css-fw.c | 5 ++---
 drivers/staging/media/ipu3/ipu3-css-fw.h | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/media/ipu3/ipu3-css-fw.c b/drivers/staging/media/ipu3/ipu3-css-fw.c
index ab021afff954..3b7df1128840 100644
--- a/drivers/staging/media/ipu3/ipu3-css-fw.c
+++ b/drivers/staging/media/ipu3/ipu3-css-fw.c

@@ -127,9 +127,8 @@ int imgu_css_fw_init(struct imgu_css *css)
 	if (css->fw->size < sizeof(struct imgu_fw_header) ||