src/drivers/vpd/vpd.c: Use C99 flexible arrays

Use C99 flexible arrays instead of older style of one-element or
zero-length arrays.
It allows the compiler to generate errors when the flexible array does
not occur at the end in the structure.

Change-Id: Iab55c57ee5cac60911c9fe4cee8d86a252bde372
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76839
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/vpd/vpd.c

@@ -25,7 +25,7 @@ struct vpd_cbmem {
 	uint32_t version;
 	uint32_t ro_size;
 	uint32_t rw_size;
-	uint8_t blob[0];
+	uint8_t blob[];
 	/* The blob contains both RO and RW data. It starts with RO (0 ..
 	 * ro_size) and then RW (ro_size .. ro_size+rw_size).
 	 */