hwrng: cctrng - Add dependency on HAS_IOMEM

The cctrng doesn't compile without HAS_IOMEM so we should depend
on it.
Reported-by: kbuild test robot <lkp@intel.com>
Fixes: a583ed31 ("hwrng: cctrng - introduce Arm CryptoCell driver")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Hadar Gat <hadar.gat@arm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/Kconfig

@@ -476,6 +476,7 @@ config HW_RANDOM_KEYSTONE
 
 config HW_RANDOM_CCTRNG
 	tristate "Arm CryptoCell True Random Number Generator support"
+	depends on HAS_IOMEM
 	default HW_RANDOM
 	help
 	  This driver provides support for the True Random Number