crypto: api - Optimise away crypto_yield when hard preemption is on

When hard preemption is enabled there is no need to explicitly
call crypto_yield.  This patch eliminates it if that is the case.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/algapi.h

@@ -442,8 +442,10 @@ static inline int crypto_memneq(const void *a, const void *b, size_t size)
 
 static inline void crypto_yield(u32 flags)
 {
+#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
 	if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
 		cond_resched();
+#endif
 }
 
 #endif	/* _CRYPTO_ALGAPI_H */