affs: struct affs_head: Replace 1-element array with flexible array

AFFS uses struct affs_head's "table" array as a flexible array. Switch
this to a proper flexible array[1]. There are no sizeof() uses; struct
affs_head is only ever uses via direct casts. No binary output
differences were found after this change.

Link: KSPP#79 [1]
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

fs/affs/amigaffs.h

@@ -80,7 +80,7 @@ struct affs_head {
  __be32 spare1;
  __be32 first_data;
  __be32 checksum;
- __be32 table[1];
+ __be32 table[];
 };
 
 struct affs_tail {