commonlib/tpm_log_serialized.h: 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: I16ac584781214350355e0625f8a2eca39a37cf85
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76841
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

src/commonlib/include/commonlib/tpm_log_serialized.h

@@ -21,7 +21,7 @@ struct tpm_cb_log_entry {
 struct tpm_cb_log_table {
 	uint16_t max_entries;
 	uint16_t num_entries;
-	struct tpm_cb_log_entry entries[0]; /* Variable number of entries */
+	struct tpm_cb_log_entry entries[]; /* Variable number of entries */
 } __packed;
 
 #endif