hw_random core is completely serialized with rng_mutex. No need for
the cycle_kernel_lock() magic.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20091010153349.844488872@linutronix.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>