hwrng: add devm_* interfaces

This change adds devm_hwrng_register and devm_hwrng_unregister which
use can simplify error unwinding and unbinding code paths in device
drivers.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --cc drivers/char/hw_random/core.c
Simple merge

diff --cc include/linux/hw_random.h
Simple merge