mtd: rawnand: ingenic: Annotate struct ingenic_nfc with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct ingenic_nfc.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Paul Cercueil <[email protected]>
Cc: Harvey Hunt <[email protected]>
Cc: Miquel Raynal <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Vignesh Raghavendra <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: Miquel Raynal <[email protected]>
Link: https://lore.kernel.org/linux-mtd/[email protected]

Author: kees

drivers/mtd/nand/raw/ingenic/ingenic_nand_drv.c

@@ -46,7 +46,7 @@ struct ingenic_nfc {
 	struct nand_controller controller;
 	unsigned int num_banks;
 	struct list_head chips;
-	struct ingenic_nand_cs cs[];
+	struct ingenic_nand_cs cs[] __counted_by(num_banks);
 };
 
 struct ingenic_nand {