signalfd: drop an obsolete comment

Commit fbe3812 ("signalfd: convert to ->read_iter()") removed the
call to anon_inode_getfd() by splitting fd setup into two parts. Drop the
comment referencing the internal details of that function.

Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Link: https://lore.kernel.org/r/20240520090819.76342-2-pchelkin@ispras.ru
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: pchelkin91

fs/signalfd.c

@@ -286,10 +286,6 @@ static int do_signalfd4(int ufd, sigset_t *mask, int flags)
 		}
 		file->f_mode |= FMODE_NOWAIT;
 
-		/*
-		 * When we call this, the initialization must be complete, since
-		 * anon_inode_getfd() will install the fd.
-		 */
 		fd_install(ufd, file);
 	} else {
 		struct fd f = fdget(ufd);