crypto: crypto4xx - fix various warnings

crypto4xx_core.c:179:6: warning: symbol 'crypto4xx_free_state_record'
	was not declared. Should it be static?
crypto4xx_core.c:331:5: warning: symbol 'crypto4xx_get_n_gd'
	was not declared. Should it be static?
crypto4xx_core.c:652:6: warning: symbol 'crypto4xx_return_pd'
	was not declared. Should it be static?

crypto4xx_return_pd() is not used by anything. Therefore it is removed.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>