isdn: fix misspelling of current function in string

Replace a misspelled function name by %s and then __func__.

In the first case, the print is just dropped, because kmalloc itself does
enough error reporting.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>