capability: fix kernel-doc warnings in capability.c

Fix all kernel-doc warnings in capability.c:

kernel/capability.c:477: warning: Function parameter or member 'idmap'
not described in 'privileged_wrt_inode_uidgid'
kernel/capability.c:493: warning: Function parameter or member 'idmap'
not described in 'capable_wrt_inode_uidgid'

Signed-off-by: Gaosheng Cui <[e-mail]>
Acked-by: Serge Hallyn <[e-mail]>
Signed-off-by: Paul Moore <[e-mail]>

kernel/capability.c

···
 /**
  * privileged_wrt_inode_uidgid - Do capabilities in the namespace work over the inode?
  * @ns: The user namespace in question
+ * @idmap: idmap of the mount @inode was found from
  * @inode: The inode in question
  *
  * Return true if the inode uid and gid are within the namespace.
···
 
 /**
  * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
+ * @idmap: idmap of the mount @inode was found from
  * @inode: The inode in question
  * @cap: The capability in question
  *