scsi: libfc: Replace one-element arrays with flexible-array members

Use flexible-array members in struct fc_fdmi_attr_entry and fs_fdmi_attrs
instead of one-element arrays, and refactor the code accordingly.

Also, this 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().

https://github.com/KSPP/linux/issues/79
https://github.com/ClangBuiltLinux/linux/issues/1590

Link: https://lore.kernel.org/r/20220214223903.GA859464@embeddedorSigned-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/libfc/fc_encode.h

@@ -246,7 +246,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
 				   &entry->type);
 		put_unaligned_be16(len, &entry->len);
 		put_unaligned_be64(lport->wwnn,
-				   (__be64 *)&entry->value[0]);
+				   (__be64 *)&entry->value);
 
 		/* Manufacturer */
 		entry = (struct fc_fdmi_attr_entry *)((char *)entry->value +

include/scsi/fc/fc_ms.h

@@ -158,7 +158,7 @@ struct fc_fdmi_port_name {
 struct fc_fdmi_attr_entry {
 	__be16		type;
 	__be16		len;
-	__u8		value[1];
+	__u8		value[];
 } __attribute__((__packed__));
 
 /*
@@ -166,7 +166,7 @@ struct fc_fdmi_attr_entry {
  */
 struct fs_fdmi_attrs {
 	__be32				numattrs;
-	struct fc_fdmi_attr_entry	attr[1];
+	struct fc_fdmi_attr_entry	attr[];
 } __attribute__((__packed__));
 
 /*