[S390] crypto: use more descriptive function names for init/exit routines.

Not very helpful when code dies in "init".
See also http://lkml.org/lkml/2008/3/26/557

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Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>