crypto: cmac - Use modern init_tfm/exit_tfm

Use the modern init_tfm/exit_tfm interface instead of the obsolete
cra_init/cra_exit interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>