dmfe: fix misspelling of current function in string

The function name contains cleanup, not clean.

This was done using Coccinelle, including the use of Levenshtein distance,
as proposed by Rasmus Villemoes.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: David S. Miller <davem@davemloft.net>