hw_random: timeriomem_rng: Allow setting RNG quality from platform data

When a hw_random device's quality is non-zero, it will automatically be
used to fill the kernel's entropy pool.  Since timeriomem_rng is used by
many different devices, the quality needs to be provided by platform
data or device tree.

Signed-off-by: Rick Altherr <raltherr@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/linux/timeriomem-rng.h

@@ -13,4 +13,7 @@ struct timeriomem_rng_data {
 
 	/* measures in usecs */
 	unsigned int		period;
+
+	/* bits of entropy per 1024 bits read */
+	unsigned int		quality;
 };